a solution contains 0.0440 m ca2+ and 0.0930 m ag+. if solid na3po4 is added to this mixture, which of the phosphate species would precipitate out of solution first? ca3(po4)2 ag3po4 na3po4 when the second cation just starts to precipitate, what percentage of the first cation remains in solution?
The percentage of the first cation that remained in the solution when the second cation starts to precipitate is 12.86%.
[tex]Ca ^{ + } in \: the \: solution \: = 0.0440[/tex]
[tex]Ag ^{ + } \: in \: the \: solution = 0.0940[/tex]
The balanced reaction for the equation is,
[tex]Ag_{3} PO _{4} →3Ag ^{3 + } + \: PO ^{3 - } _{4}[/tex]
[tex]Solubility \: product \: constant \: of[/tex]
[tex]Ag_{3} PO _{4} = 8.89 \times 10 ^{ - 17} [/tex]
[tex]k _{s} =[Ag ^{ + } ]^{3} \: [PO _{4} ^{3 - } ] [/tex]
[tex]8.89 \times 10 ^{ - 7} = (0.940) ^{3} \: [PO _{4} ^{3 - } ] [/tex]
[tex] \frac{8.89 \times 10 ^{ - 7}} { (0.940) ^{3}} = \: [PO _{4} ^{3 - } ] [/tex]
[tex] [PO _{4} ^{3 - } ] = 1.07 \times 10 ^{ - 13} [/tex]
The balanced equation for the reaction is,
[tex]Ca_{3} (PO _{4}) _{2}→3Ca ^{2 + } + 2PO _{4} ^{3 - } [/tex]
[tex]The \: solubility \: product \: constant \: of [/tex]
[tex]Ca_{3} (PO _{4}) _{2} = 2.07 \times 10 ^{ -32} [/tex]
[tex]k _{s} = [Ca ^{ 2 + } ] ^{ 3} \: (PO _{4}) _{2}[/tex]
[tex]2.07 \times 10 ^{ - 33} = (0.0440)^{3} \: (PO _{4} ^{3 - } )^{2} [/tex]
[tex] [PO _{4} ^{3 - } ] = \frac{2.07 \times 10 ^{ - 33} }{(0.0440)^{3} }[/tex]
[tex](PO _{4} ^{3 - }) = 4.93 \times 10 ^{ - 15} [/tex]
[tex]Ca_{3} (PO _{4}) _{2} \: will \: precipitate \: first.[/tex]
[tex]Concentration \: of \: Ca ^{ + 2} \: when \:[/tex]
the second cation starts to precipitate.
[tex]k _{s} = [Ca ^{ + 2} ] ^{ 3} \: (PO _{4} ^{3 - } ) ^{2} [/tex]
[tex]2.07 \times 10 ^{ - 33} = [Ca ^{ + 2}] ^{3} \: \times 10 ^{ - 33} [1.07 \times 10 ^{ - 13} ] ^{2} [/tex]
[tex] [Ca ^{ + 2}] = 0.00566[/tex]
The percentage of the first cation that remained in the solution when the second cation starts to precipitate is,
[tex]percentage \: \: of \: remaining \: Ca ^{ + 2} = \frac{concentration \: remaining}{initial \: concentration } [/tex]
[tex] = \frac{0.00566}{0.044} \times 100[/tex]
= 12.86 %
Therefore, the percentage of the first cation that remained in the solution when the second cation starts to precipitate is 12.86%.
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An electrically neutral atom of beryllium has four protons. Which statement is true? There are four protons in the nucleus. There is a charge of −4 on an atom of beryllium. There are four neutrons in the nucleus. There is a charge of +4 on an atom of beryllium.
Answer:
there are four protons in the nucleus
An object displaces 15.9ml when it is submerged in water. What is the volume of the object in liters?
Answer:
0.0159 Liters
Explanation:
15.9 ÷ 1E3 aka 1000 = 0.0159 liters
milli means 1000 of something
which one of the following carbonyl compounds has the highest percentage of enol when keto-enol equilibrium has been established?
When keto-enol equilibrium has been reached, the compound with the largest percentage of enol is 1,2 cyclo hexanedione.
1,2-cyclohexanedioneThe chemical compound 1,2-cyclohexanedione has the formula (CH2)4(CO)2. It is one of three cyclohexanediones that are isomeric.
It is a substance with no colour that dissolves in a number of organic solvents. It can be made by using selenium dioxide to oxidise cyclohexanone.From this di ketone, numerous diimine and dioxime ligands have been created. In order to produce diaza heterocycles, it condenses with 1,2-diamines.chemical formula: C6H8O21.1305 g/cm3 is the density.Molecular weight: 112.128 g/molCyclohexane-1,2-dione hydrolase, a novel tool to degrade alicyclic molecules, is studied using 1,2-cyclohexanedione as a substrate. Additionally, it serves as a particular reagent for arginine residues.learn more about keto-enol equilibrium here
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Convert a volume of 2650 cm³ to cubic meters.
Answer:
0.00265m³
Explanation:
from cm³ to m³, divide by 1000000.
2650/1000000
=0.00265m³
hydrogen fuel can be produced from methane or by electrolysis of water. as of 2020, the majority of hydrogen (∼95%) is produced from fossil fuels by steam reforming or partial oxidation of methane and coal gasification with only a small quantity by other routes such as biomass gasification or electrolysis of water.
Natural gas contains methane (CH[tex]4[/tex]), which is used to produce hydrogen by thermal processes like stem-methane reformation and partial oxidation.
In steam-methane reforming, which is the most common method to produce hydrogen, high temperature steam (700°C - 1000°C). The pressure required is 3-25 bar pressure, in the presence of a catalyst. Steam reforming is an endothermic process. Carbon monoxide and steam are reacted using catalyst to produce carbon dioxide and hydrogen.
Partial oxidation is an exothermic process. It is much faster than steam reforming. This method initially produces less hydrogen.
These processes are more preferred because the use of petroleum is low and the emissions is also low. Total greenhouse gases emission is cut.
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Write the value represented by 4.5x10-6 g
0.0000045 g
450,000 g
4,500,000 g
0.00000045 g
the value represented by 4.5x10-6 g is 0.0000045 g it is a representation in standard notation
To express enormous figures which are in standard notation like 1,300,000 or exceedingly minuscule quantities like 0.0000000000045, scientists use scientific notation. Scientific notation, also referred to as exponential form, is one of the earliest mathematical techniques. It is well regarded by practitioners. People use scientific notation to handle situations where numbers are too large or too small to be calculated easily. Scientists, engineers, and mathematicians all use this technique. where as standard notation is way writing numbers in normal decimal form. The scientific method id most convenient denoting numbers as the numbers will be either too big or too small.
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a piece of copper metal is initially at 100.0°c. it is dropped into a coffee cup calorimeter containing 50.0 g of water at a temperature of 20.0°c. after stirring, the final temperature of both copper and water is 25.0°c. what is the mass of copper piece used?
The mass of copper piece use is 13.9 J/K
We are given:
• Initial temperature of copper, [tex]T_{Cu, i}[/tex] = 100°C
• Mass of water, [tex]m_{water}[/tex] = 50 g
• Initial temperature of water,[tex]T_w, i[/tex] = 20°C
• Final temperature, [tex]T_f[/tex] = 25°C
• Specific heat capacity of water, [tex]c_{water}[/tex]= 4.18 J/gK
From the given information, we need to determine the heat capacity of the copper ( [tex]C_{Cu}[/tex]).
The heat released by the copper can be calculated as:
[tex]Q_{Cu}=C_{Cu}(T_{f } - T_{Cu, i})[/tex]
While the heat absorbed by the water can be calculated as:
[tex]Q_{water}=m_{water}c_{water}(T_{f } - T_{w, i})[/tex]
we can assume that the heat released by the copper is just fully absorbed by the water. The sum of the two heats is zero.
[tex]Q_{Cu} + Q_{water } = 0[/tex]
[tex]C_{Cu}(T_f - T_{Cu, i}) + m_{water}c_{water}(T_f - T_{w,i} ) = 0[/tex]
Since we want to calculate the heat capacity of copper, we can rearrange the equation to obtain an equation for [tex]C_{Cu}[/tex].
[tex]C_{Cu}= \frac{ m_{water}c_{water}(T_f - T_{w,i} )} {(T_f - T_{Cu, i})}[/tex]
Since we are given the necessary information to solve the problem, we can just substitute the given values in the equation. Please note that the difference in temperatures in Kelvin is the same as the difference in temperatures in °C. So in this case, we can simply plug in the temperature values without changing them to Kelvin first.
[tex]C_{Cu}= \frac{ m_{water}c_{water}(T_f - T_{w,i} )} {(T_f - T_{Cu, i})} = \frac{(50g)(4.18J/gK)(25\textdegree C - 20\textdegree C)}{25\textdegree C-100\textdegree C}[/tex]
[tex]C_{Cu} = 13.9 J/K[/tex]
Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature.
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Work Right, Work Safe at School and at Home
A laboratory is any area where science investigation occurs. Even your kitchen can be considered as one. What laboratory tools or equipment can be substituted with kitchen-wares? Choose five tools found in the laboratory and give a kitchenware that can serve as a substitute for each.
Laboratory Tools Kitchen-wares Substitute
Name:
Drawing/Illustration:
Use:
Name:
Drawing/Illustration:
Use:
Name:
Drawing/Illustration:
Use:
Name:
Drawing/Illustration:
Use:
Name:
Drawing/Illustration:
Use:
QUESTIONS:
1. Why is it important to know the use of laboratory tools and equipment? Give at least two reasons.
2. Why must working safe be practice in the laboratory?
A. Hot Plate - Materials are heated using hot plates. A stove may readily take the place of this equipment.
B. Test Tube Holder - Kitchen tongs, which come in various sizes, can be utilized in the absence of test tube holders.
C. Beakers and flasks are used for both measuring liquids and combining various ingredients. At home, measuring cups and measuring spoons can take their place because they are wide or tall enough to be used for mixing and still have the ability to be used to measure the ingredients.
D. Stirring Rod - A stirring rod can be replaced by a variety of items. Chopsticks are an example because of their similar shape, as are spoons, ladles, and forks if the container allows them.
E. Funnel - Typically, the material used to make a kitchen funnel and a laboratory funnel is the sole distinction. Kitchen funnels are often made of plastic, whereas laboratory funnels are made of heat-resistant glass. Nevertheless, as long as it is not exposed to extremely high temperatures, it can still perform the duties of a standard laboratory funnel.
1. Before conducting any type of experiment, you should always be familiar with your lab's equipment because, without it, you won't know how to use your materials or how to fix a mistake you might make with it.
2. You may aid in preventing or eliminating hazards by being familiar with the laboratory you're working in and by constantly adhering to the correct safety protocols. Additionally, you'll be aware of what to do in the unfortunate case that something goes wrong.
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Pls guy's.
state the periodic law. I need it now
Explanation:
The Periodic Law states that the physical and chemical properties of the elements recur in a systematic and predictable way when the elements are arranged in order of increasing atomic number. Many of the properties recur at intervals. When the elements are arranged correctly, the trends in element properties become apparent and can be used to make predictions about unknown or unfamiliar elements, simply based on their placement on the table.
Answer:
The periodic law states that, "properties of the elements very periodically with their Relative Atomic Mass
Explanation:
Then the modern periodic law states that, "The chemical and physical properties of element are a periodic function of the atomic number"
Hope it helps
An adult patient who weighs 135 pounds is given 10.0 mL of a different liquid medicine. The label states that each
teaspoon of the medicine mixture contains 75 mg of active ingredient. What dose, in mg/kg, has bee
administered to this patient? Information with the medicine indicates that 3.3 mg/kg is the maximum
recommended dose. Has this patient received an overdose?
The patient has not received an overdose because only 150 mg of the drug was given instead of 202.488mg which is the maximum recommended dose.
Calculation of drug dosageThe weight of the patient= 135lb
The weight of patient in Kg is calculated as follows,
1 kg = 2.2lb
Xkg = 135Ib
Xkg= 135/2.2
Xkg = 61.36kg
The maximum recommended dose for the drug = 3.3mg/kg
That is, if 3.3 mg = 1 kg
Xmg = 61.36kg
Xmg = 61.36 × 3.3 = 202.488mg
The number of teaspoon administered = 2 = 10ml each containing 75mg of the drug.
The patient received 75 mg ×2 = 150mg of drug.
Therefore, the patient has not received an overdose because only 150 mg of the drug was given instead of 202.488mg which is the maximum recommended dose.
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what value would you put the NUMERATOR of this calibration? please help t
The value that would be put in the numerator of this calibration would be 10° C .
The process of calibrating an instrument involves setting it up such that it can produce results for samples that are within a reasonable range. A key component of instrumentation design is eliminating or reducing conditions that lead to faulty measurements.
In order to ascertain the mistake or confirm the precision of the unknown value of the DUT, a calibration is normally carried out. As a simple illustration, you may calibrate a DUT thermometer by measuring its temperature in water at its known boiling point (212 degrees Fahrenheit) in order to determine the thermometer's inaccuracy.
To obtain accurate readings, a thermometer must be calibrated because its precision is susceptible to deterioration over time. Thermometers can change over time for a variety of reasons.
Hence, The value that would be put in the numerator would be 10° C because difference between two marked values or space between two marked value is 10.
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5.the acyl group is a protecting group for amines which can be deprotected by treatment with sodium hydroxide. please write mechanisms for both the protection and deprotection steps
Protecting Groups for Amines:
Amine protecting groups are essential for the synthesis of peptides.Carbamates are useful protecting groups for amines. They can be installed and removed under relatively mild conditions.One of the most common carbonate protecting groups is the t-butyloxycarbonyl (Boc) protecting group. It can be removed with strong acid (trifluoro acetic acid) or heat.The carboxybenzyl (CBz) group has a benzyl group and can be removed using catalytic hydrogenation (Pd-C, H₂)The fluorenyl methoxy (FMoc) group can be removed with an amine base (e.g. R₂NH)If multiple protecting groups are present on the same molecule, it's useful to choose them such that they can each be removed under different sets of conditions (e.g. acidic, basic, hydrogenation).Learn more about Protecting Groups for Amines are:
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In simple summary form, the calvin cycle requires an input of __________ for every product that is formed and the output product is __________, which is used for glucose synthesis.
In simple summary form, the calvin cycle requires an input of 3 CO₂ for every product that is formed and the output product is a three-carbon molecule, which is used for glucose synthesis.
Calvin cycle is light-independent (dark) reactions or carbon reactions.
In photosynthesis (convert light energy into chemical energy), the carbon in carbon(IV) oxide is being reduced to form glucose.
The pigment chlorophyll absorbs one photon and loses one electron (it passed throw an electron transport chain) in the light-dependent reactions.
The enzyme RuBisCO takes carbon(IV) oxide in the light-independent reactions.
During Calvin cycle, three molecules of carbon dioxide (CO₂) are combined with hydrogen ions to form three carbon-molecules (see the picture).
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2. in nature the element neon exists as three different isotopes, ne-20, ne-21, and ne-22. which neon isotope predominates? explain your choice.
The three isotopes of Neon, Ne-20, Ne-21, and Ne-22 are said to have an atomic number. Neon - 20 with a mass of 19.99 amu predominate all other isotopes.
What are isotopes?Isotopes as been defined as atoms of the same element with different atomic masses but the same atomic number as the number of neutrons differs in the atoms. The neon element has three isotopes, Ne-20, Ne-21, and Ne-22.
Ne - 20 is the most predominant isotope of the Neon element as it most abundant and stable isotope with an abundance of 90.48% followed by Ne-22 (9.25%), and Ne-21 (0.27%).
Therefore, Ne-20 is a predominant isotope of Neon.
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the atom that contains only one electron in the highest occupied energy sublevel (a) s (b) ca (c) ga (d) sb (e) br
The atom that contains only one electron in the highest occupied energy sublevel is (c) Ga
A sublevel is the division of the principle energy levels. There are infinite numbers of sublevels but the defined are: s, p, d and f.
The abbreviated "s" is for sharpThe abbreviated "p" is for principleThe abbreviated "d" is for diffuseThe abbreviated "f" is for fundamentalThese energy levels are used to predict and explain the chemical bonds which atoms can form. The equation that allows for finding the distributions for an electron is the Schrodinger's equation.
For the options gave we have the following sublevels:
(a) S = [Ne] 3s2 3p4
(b) Ca = [Ar] 4s2
(c) Ga = [Ar] 3d10 4s2 4p1
(d) Sb =[Kr] 4d10 5s2 5p3
(e) Br = [Ar] 4s2 3d10 4p5
As we can see the only atom that has one electron in the highest occupied energy sublevel is Gallium
What is an atom?The atom is the smallest part of the composition of matter, it is indivisible and is composed of a nucleus that has protons and neutrons, and around the nucleus there are the electrons.
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A scientist monitors the reaction between two gases in a closed container. What would happen to the rate of the reaction if the scientist increases the temperature in the container?
The rate would increase because higher temperature would increase the number of collisions.
The rate would decrease because the particles are unable to achieve the correct orientation.
The rate would decrease because the space available for the reactions would decrease.
The rate would increase because the average speed of the reactant particles would decrease.
A scientist monitors the reaction between two gases in a closed container and the rate would increase if the scientist increases the temperature in the container because higher temperature would increase the number of collisions .
So , first option is correct one .
In the closed vessel the pressure is constant . So, we already know that temperature affects a reaction's rate . The rate of a reaction increases with temperature . For instance, the time needed to melt a metal will be substantially longer at a lower temperature than it will be once the temperature is increase .
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Which of the following sets of values is correct for Bromine-80 (Br, #35), which has a mass of 80? (1 pt)
*
1 point
80 protons, 80 electrons, 80 neutrons, 8 valence electrons
45 protons, 45 electrons, 80 neutrons, 7 valence electrons
45 protons, 45 electrons, 35 neutrons, 8 valence electrons
35 protons, 35 electrons, 45 neutrons, 7 valence electrons
35 protons, 45 electrons, 35 neutrons, 2 valence electrons
How can you distinguish between crystalline allotropic modifications of Sulphur from those of amorphous allotrops?
The crystalline allotropes of sulfur are very strong and have a high melting and boiling point while the amorphous allotropes of sulfur are brittle and breaks easily.
What is a crystalline substance?A crystalline substance is one that has a definite arrangement of the atoms in the substance. An amorphous substance lacks this definite arrangement. We can see this arrangement when we conduct an X-ray crystallography of the sulfur.
Also, the crystalline allotropes of sulfur are very strong and have a high melting and boiling point while the amorphous allotropes of sulfur are brittle and breaks easily.
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a mixture of caco₃ and cao has a mass of 2.500 g. after heating, the mass of the sample is reduced to 2.016 g. what is the mass percent of caco₃ in the mixture? caco₃(s) → cao(s) co₂(g)
There is 44 % of CaCO3 in the mixture
Step 1: Data given
Mass of mixture = 2.500 grams
Mass after heating = 2.016 grams
Step 2: The balanced equation
CaCO3 → CO2 + CaO
Step 3: Calculate mass CO2 lost
Mass CO2 lost = Mass before heating - mass after heating
Mass CO2 = 2.500 - 2.016 = 0.484 grams
Step 4: Calculate the mole's CO2
Moles CO2 = Mass CO2 / molar mass CO2
Moles CO2 = 0.484 grams / 44.01 g/mol
Moles CO2 = 0.0109 moles
Step 5: Calculate moles CaCO3
For 1 mol CaO we need 1 mol CO2 for 1 mol CaCO3
For 0.0109 mol CO2, we have 0.0109 mol CaCO3
Step 6: Calculate the mass of CaCO3
Mass CaCO3 = moles CaCO3 * molar mass CaCO3
Mass CaCO3 = 0.0109 moles * 100.08 g/mol
Mass CaCO3= 1.10 grams
Step 7: Calculate the mass per cent of CaCO3
Mass % CaCO3 = (
There is 53.8 % of CaCO3 in the mixture 1.10 grams / 2.750 grams )*100 %
Mass % CaCO3 = 44 %
The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilograms of carbon 12.
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Explain the role of photosynthesis in the flow of energy between the plant and the person shown in the diagram.
plant and the person
Sunlight energy can be converted by photosynthesis into chemical energy in the form of carbohydrates, which can then be used by the body for cellular respiration. Humans employ oxygen and carbohydrates, the byproducts of photosynthesis, to create energy, water, and carbon dioxide. Human breath carbon dioxide is used by the plant to complete photosynthesis.
Green plants and certain other organisms convert light energy into chemical energy through a process called photosynthesis. Light energy is gathered and utilized during photosynthesis in green plants to change the water, carbon dioxide, and minerals into oxygen- and energy-rich organic molecules.
It is impossible to overstate the role that photosynthesis plays in sustaining life on Earth. There would soon be little food or other organic materials on Earth if photosynthesis stopped. The majority of life would vanish, and eventually, the atmosphere of Earth would contain almost no gaseous oxygen. Only chemosynthetic bacteria, which can use the chemical energy of specific inorganic substances and are not reliant on the conversion of light energy, would be able to survive in such an environment.
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under one set of conditions, the substances in a and b mix and the result is depicted in c. does this represent a chemical or a physical change?chemical changephysical changeb) under a second set of conditions, the same substances mix and the result is depicted in d. does this represent a chemical or a physical change?chemical changephysical changec) under a third set of conditions, the sample depicted in c changes to that in d. does this represent a chemical or a physical change?chemical changephysical changed) when the change in part (c) occurs, does the sample have different chemical properties? physical properties?yes, different chemical propertiesyes, different physical properties
a) The substances in A and B mix and the result is depicted in C is chemical change.
b) The substances in A and B mix and the result is depicted in D is chemical change.
c) Under a third set of conditions, the sample depicted in C changes to that in D is a kind of physical change.
d) When the change in part (c) occurs both the sample formed have same chemical properties.
In first case,
When the substances A and B mix and the result is depicted in C this implies that A and B react to give another substance C. Since C contain atoms of both A and B therefore, it have different property than A and B. So, it is a kind of chemical change.
In second case,
When the substances A and B mix and the result is depicted in D this implies that A and B react to give another substance D in different set of condition. Since D also contain atoms of both A and B therefore, it also have different property than A and B. So, it is a kind of chemical change.
In third case,
As we know that C and D both formed by the reaction between A and B in different set of conditions. So, we can say that C and D basically differ from each other in terms of state. So, C can be converted into D by either cooling or boiling. So, it is a kind of physical change.
In fourth case,
Since, we found that both C and D are differ in state of matter but they have same Chemical properties as both are formed of A and B. So, we can say that, C and D have same chemical properties but have different Physical properties.
Thus, we concluded that when A and B react to form C and in other case form D it is Chemical change. When C converted into D, it is physical change while both have same chemical properties.
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Using the periodic table above and your knowledge of patterns and trends on the table, which of the following elements has the highest electronegativity? (1 pt)
*
1 point
Titanium (Ti, #22)
Silicon (Si, #14)
Oxygen (O, #8)
Argon (Ar, #18)
Use the table of observed changes to answer the question. Change # Reacts with another substance? Temperature change? Gas, sound, or light produced? New substance formed? 1 yes yes yes yes 2 no yes yes no 3 yes yes yes yes 4 no no no no Which changes shown in the table are physical changes? (1 point) 1 and 4 1 and 4 2 and 3 2 and 3 1 and 2 1 and 2 2 and 4 2 and 4
Option 4- no, no, no, no. (for physical change.)
Chemical Change -A chemical change is the conversion of one substance into another, the development of new chemicals with unique features, or any combination of these.
There are five (simple) methods for identifying a reaction:
1. change of color
2. Gas formation
3. pH change
4. Temperature change
5. Precipitate formation
Physical change - A physical change happens when a substance's physical characteristics change without undergoing chemical composition. Common physical changes include melting, adjustments to size, volume, color, density, and crystal structure.
Therefore, according to the question physical changes are-
1. Reacts with another substance- no
2. Temperature change - no
3. Gas, sound, or light produced - no
4. New substance formed - no
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Classify each of the following reactions as either exothermic or endothermic: 2H,O(l) + heat → 2H₂(g) + O₂(g)
Answer:
endothermic
Explanation:
It is endothermic since it absorbs heat. If the reaction RELEASED heat (exothermic) the "+ heat" would be on the right side of the equation.
Name
Between August 24, 15:00, and August 26, 03:00, the wind speed for
Hurricane Andrew remained essentially the same. Where was
Hurricane Andrew located during this period of time?
Answer:
Andrew made landfall at 5 a.m. as a Category 5 — at the time only the third Category 5 to land on U.S. soil — just south of Miami with top winds at 165 mph and a 16.9-foot storm surge
Explanation:
(HURRY 6. What happens during the phase change of condensation?
liquid turns into solid
gas turns into solid
liquid turns into gas
gas turns into liquid
D
Explination: During condensation, a substance is changed from the gaseous to the liquid state of matter. Vaporization, which is more often referred to as "boiling," is the complementary process in which a chemical is converted from the liquid state of matter to a gaseous physical form.
When methanol, ch3oh, is burned in the presence of oxygen gas, o2, a large amount of heat energy is released. For this reason, it is often used as a fuel in high performance racing cars. The combustion of methanol has the balanced, thermochemical equation.
To produce 807 kJ of heat, 33.85g of methanol ([tex]CH_3OH[/tex]) must be burned.
When -764.0 kJ of heat is involved, 1 mol of methanol, [tex]CH_3OH[/tex] is reacting
Therefore, mol of [tex]CH_3OH[/tex] for -8.07 x [tex]10^2[/tex] kJ:
= -8.07 x [tex]10^2[/tex] x 1/-764.0 kJ
= 1.056 mol
Molar mass of methanol ([tex]CH_3OH[/tex]),
MM = 1 x MM(C) + 4 x MM(H) + 1 x MM(O)
= 1 x 12.01 + 4 x 1.008 + 1 x 16.0
= 32.042 g/mol
mass of methanol ([tex]CH_3OH[/tex]) used:
Mass, m = number of mol x molar mass
= 1.056 mol x 32.04 g/mol
= 33.85 g
Hence, 33.85g of methanol ([tex]CH_3OH[/tex]) must be burned to produce 807kJ of heat.
The complete question is:
When methanol, [tex]CH_3OH[/tex], is burned in the presence of oxygen gas, [tex]O_2[/tex], a large amount of heat energy is released. For this reason, it is often used as a fuel in high performance racing cars. The combustion of methanol has the balanced, thermochemical equation
[tex]CH_3OH (g) + 32O_2 (g) \rightarrow CO_2 (g) + 2H_2O (l)[/tex] Δ= −764 kJ
How much methanol, in grams, must be burned to produce 807 kJ of heat?
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Which model of the atom has electrons traveling in specific paths around the nucleus?
A. Thomson’s model
B. Rutherford’s model
C. Bohr’s model
D. Dalton’s model
Answer:
C
Explanation:
this is because the rest talk about the findings of protons,neutrons and electrons.
Ions form the _____ number of an atom is changed
A proton
B neutron
C electron
D atomic number
Ions form the proton number of an atom is changed. The correct option is A.
Thus, An atom will be neutrally charged if its protons and electrons are equal in number. An ion is created when an atom's protons and electrons are different numbers.
It is technically possible to make an ion if the number of protons varies but the number of electrons stays the same. The identity of the atom is determined by the amount of protons, not by the atom itself, which will change.
An isotope would be produced if the neutron count varied. An ion will also form if the number of electrons changes because this will cause a change in charge.
Thus, Ions form the proton number of an atom is changed. The correct option is A.
Learn more about Protons, refer to the link:
https://brainly.com/question/12535409
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