Answer:
The last option. Because it's not a curate or precise on the dot.
for the measurements 0.123 m, which digits is the estimated digit?
Answer:
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Explanation:
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when all quantum numbers are considered, how many different quantum states are there for a hydrogen atom with n
When all quantum numbers are considered, there are three (3) quantum states for hydrogen atoms.
The 3 quantum numbers of hydrogen is n, l and m.
n = principal quantum number, l = angular momentum quantum number,
m = angular momentum projection quantum number.
The hydrogen atom is simple and consists of a single negatively charged electron which moves around a proton which is positively charged. For hydrogen atom of specific energy, the number of states depends on the angular momentum. The total energy depends on the principal quantum.
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Two or more substances in variable proportions where the composition is constant throughout are.
Answer:
homogenous mixture
Explanation:
no choices are given so that is my best guess
Transferring small quantities of liquid solutions from one container into another
Using Pasteur Pipettes (or pipets) are the most commonly used tool for transferring small volumes of liquids (< 5mL) from one container to another.
What is Pasteur Pipettes?A pipette, also called pipett, is a lab instrument frequently used in the fields of chemistry, biology, and medicine to transfer a predetermined volume of liquid, frequently as a media dispenser. Pipettes are available in a variety of styles with varying degrees of accuracy and precision, ranging from simple single-piece glass pipettes to more intricate adjustable or electronic pipettes. In order to draw liquid up and out of a pipette, a partial vacuum is often created above the liquid-holding chamber and then selectively released. Depending on the instrument, measurement accuracy varies substantially.
Although each form of pipette has particular descriptive titles, in practice any sort of pipette will only be referred to as a "pipette," and the required device will be clear from the context. Occasionally, pipettes that dispense.
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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
what is the simple unit factor that relates the number of hydrogens in sucrose to the number of oxygens?
The simple unit factor that relates the number of hydrogens in sucrose to the number of oxygens is:
2 moles hydrogen = 1 mole of oxgen
Formula of sucroseThe formula of sucrose is given as follow:
C₁₂H₂₂O₁₁
From the formula, we obtained the following
12 moles of carbon22 moles of hydrogen11 moles of oxygen How to determine the unit that relates hydrogen and oxygen1 mole of C₁₂H₂₂O₁₁ contains:
22 moles of hydrogen11 moles of oxygenThus, the unit factor that relates hydrogen and oxygen can be obtained as follow:
Hydrogen / Oxygen = 22 / 11
Hydrogen / Oxygen = 2 / 1
Thus,
2 moles hydrogen = 1 mole of oxgen
Thus, for every mole of oxygen, there are 2 moles of hydrogen
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PLEASE HELP!! I need to know the answer to this but I'm overly exhausted and the question isn't making and sense...
An unknown element has three naturally occurring isotopes.
Below are their masses (amu) and % abundance
A) Calculate the weighted atomic mass unit for each isotope. Show % conversions and record the AMU for each isotope in the table below
B) What is the average (Total) atomic mass unit of the unknown element.
C) Identify this unknown element from the Periodic Table
An unknown element has three naturally occurring isotopes total average atomic mass 20.18 amu and element from the periodic table is neon
Isotopes are the members of a family of an element that all have the same number of protons but different numbers of neutrons
There are three neon isotopes and the more abundant ²⁰Ne and ²¹Ne are both essentially all primordial, as there is no significant global production of these isotopes and also ²²N
Neon 20 is made up of ten proton and ten neutron the atomic mass unit of the gas is 19.992 and the abundance of the gas is 90.48% and neon 21 is made up of ten proton and eleven neutron and the atomic mass unit of the gas is 20.994 and the abundance is 0.27% and neon 22 is made up of ten proton and twelve neutron and the atomic mass unit of the gas is 21.991 and the abundance of gas is 9.25%
Unknown element from the periodic table is neon
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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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(b) .In an experiment, carbon (IV)oxide gas as passed over heated charcoal and the gas produced collected as shown in the diagram below Write an equation for the reaction that took place in the combustion tube (1mk)
When carbon (IV)oxide gas is passed over heated charcoal ,the gas produced is Carbon Monoxide.
The oxidation state of carbon (II) oxide, often known as carbon monoxide, is +2. It is the suffocating gas created when gasoline in car engines burns inefficiently. Colorless, tasteless, odorless, and somewhat less dense than air, carbon monoxide is a gas. It is formed due to incomplete combustion of CO2. Carbon monoxide is much more threatening than CO2.
When carbon (IV)oxide gas is passed over heated charcoal ,the gas produced is Carbon Monoxide is Carbon (II) oxide is formed.
When coke or red-hot carbon is passed through carbon (IV) oxide, it is created.
The equation for the reaction is-
CO₂(g) + C(s) → 2CO(g)
Hence, Carbon monoxide is formed when Carbon dioxide is passed over heated charcoal.
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Which periodic trend is not explained by shielding and ENC?
O Atomic radius
O ENC does not explain any periodic trend
O ENC explains all periodic trends
O
Electronegativity
ENC explains all periodic trends
The electrostatic attraction between the positively charged nucleus and the negatively charged electrons holds electrons in an atom or ion. Due to electron shielding that exists between the electron of interest and the nucleus in multi-electron species, the electrons do not experience the full positive charge of the nucleus. The effective nuclear charge is the total positive charge that really affects an electron.
In order to comprehend periodic characteristics, it is crucial to understand the idea of effective nuclear charge (Z*). The portion of the total nuclear charge that an electron in an atom experiences is known as the effective nuclear charge. This is equal to the atomic number (Z) less the amount () by which other atoms' electrons protect the particular atom's nucleus.
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What is Electron gain Enthalpy?
Answer:
Electron gain enthalpy is defined as the amount of energy released when an electron is added to an isolated gaseous atom.
pls help!
EXPERIMENTAL QUESTION: How does the amount of substance affect the rate at which temperature changes?
HYPOTHESIS: If the mass of a sample of water is increased, then the rate at which its temperature changes will be ____________________.
increased
decreased
Answer:
I'm guessing you are asking for the word that will make the hypothesis correct. In that case, it would be:
"If the mass of a sample of water is increased, then the rate at which it's temperature changes will be decreased."
Explanation:
Mass and temperature have an inverse relationship, so when one of the values increase, the other decreases. On Study.com there is more on this subject. I will put a link for you :)
https://homework.study.com/explanation/how-does-the-amount-of-a-substance-affect-the-rate-at-which-temperature-changes.html#:~:text=For%20a%20given%20amount%20of,a%20smaller%20increase%20in%20temperature.
I hope this helps!
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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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.
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
Calcium carbonate decomposes into calcium oxide and carbon dioxide. If 224 g of calcium carbonate decomposes, how many moles of carbon dioxide gas is produced?.
When 224 g of calcium carbonate(CaCO3) decomposes , 2.24 moles of carbon dioxide is produced.
When calcium carbonate decomposes in the presence of heat, it produces calcium oxide and carbon dioxide. This reaction is represented by the following equation:
CaCO3 ⇒ CaO + CO2
It is clear from the above equation that,
1 mole of CaCO3 produces 1 mole of CO2
Or 100 g of CaCO3 produces 1 mole of CO2
Thus, 224 g of CaCO3 produces 1/100 x 224 = 2.24 moles of CO2
Therefore, if 224 g of calcium carbonate(CaCO3) decomposes, 2.24 moles of carbon dioxide is produced.
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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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Why is it important to water your house plants?
So they can have nutrients from the water to keep it from not dying
Answer:
Plants need water to grow. Plants are about 80-95% water and need water for multiple reasons as they grow including for photosynthesis, for cooling, and to transport minerals and nutrients from the soil and into the plant.
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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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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Which example shows an organism that cannot reach homeostasis through internal changes?
Responses
A lizard is cold, and it moves to a sunny rock to warm up.
A dog shivers when it is too cold.
Circulation decreases in a bird when it becomes too warm.
.
A person gets a fever in response to a flu infection.
Select the correct answer. what is tempera? a. pigment mixed with egg yolk as a binder. b. pure, undiluted pigment. c. pigment made from zinc and cobalt.
The correct answer is (A) pigment mixed with egg yolk as a binder.
A natural emulsion that is water-soluble, such as glue, honey, milk in the form of casein, or a variety of plant-based gums, can hold pigment in tempera, a painting media.
Using tempera, you can blend the essential colours as you go while creating the paint from scratch. Although it should be noted that some pigments require more binder than others and that the more egg added, the more transparent the resultant paint will be, mixes should begin with an equal volume of pigment and binder.
From the early 1500s, when oil paints started to gain popularity, tempera served as the main painting medium, it was employed for icon painting and painted panels in churches, and it is still utilised today.
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Some lipid rafts are characterized by an accumulation of cholesterol. What does this mean for the fluidity of the lipid raft?.
The lipid rafts are less fluid than the surrounding membrane at normal temperatures.
Cholesterol decreases the fluidity of the membrane at normal temperatures.
Lipid rafts regulate neurotransmission, receptor traffickinging and influence membrane fluidity.
Membrane fluidity refers to the viscosity of the lipid bilayer.
Cholesterol in the rafts has a potential to effectively control the ion conductance and excitability of membranes.
For example, in phospholipid layer in cell membrane, there are hydrophilic heads (polar part of the layer) and hydrophobic tails (nonpolar part of the layer).
1) Small, non-polar molecules diffuse easily through this layer, no energy is required, this is passive transport.
2) Polar molecules cannot diffuse through phospholipid layer using passive transport, because hydrophobic tails does not allow that (polar molecules are reppeled), energy is required for that, this is active transport.
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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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An isotope has an atomic number of 36 and contains 44 neutrons. What is the isotope’s mass number?
the isotopes mass number is 36
Explanation:
because atomic number is also mass number
Which of these is true for a molecular model like the one shown ? A. We can always identify the type of each atom based on color. B. The model shows how the various atoms are connected in the molecule. C. The model shows the actual size of each atom correctly D. The model shows the relative sizes of the atoms to each other.
The true statement about the model is that the model shows how the various atoms are connected in the molecule.
What is a molecular model?A molecular model is a representation of a molecule. We know that the molecular model shows the extent to which the atoms are bonded in the compound. The model gives us an idea of the intricate atom to atom arrangement that exists in the molecule that is under study.
Now we know that the atoms that are in the models must be shown by the use of different colors. This enables us to be able to effectively and properly distinguish between the atoms of the compound as shown in the model.
The true statement about the model is that the model shows how the various atoms are connected in the molecule.
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triaryl-1,3,5-triazinane-2,4,6-triones (isocyanurates) peripherally functionalized by donor groups: synthesis and study of their linear and nonlinear optical properties
the synthesis study of triaryl-1,3,5-triazinane-2,4,6-triones is functionalized by d6-transition metal acetylides complexes at their periphery .
triaryl-1,3,5-triazinane-2,4,6-triones (isocyanurates) peripherally functionalized by donor groups: The linear optical (LO) and nonlinear optical (NLO) properties of a series of isocyanurates functionalized by donor's arms at the periphery. These octupolar derivatives were obtained from commercial isocyanate derivatives several of these derivatives exhibit remarkable transparency or activity/ tradeoffs. In third‐order activity, the stronger donor groups (X=NH2, NMe2, or NPh2) with the longer derivatives possess effective two‐photon absorption cross sections displayed for the extended arylamino cyclotrimers. to rationalize their non linear properties and unravel their electronic structures DFT computations were also performed.
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based on the law of multiple proportions, how many grams of hydrogen would you expect 2.19 g of nitrogen to combine with to yield ammonia?
We're going to use 0.34 grams of nitrogen to resolve this. This would have a molar mass of, uh, 28 2 grams if we converted these two moles. Wu will then combine this as well. One-mole play is also a thing. three of H 2's moles. Grams of hydrogen are what we need. We will learn the answer here. Hydrogen weighs two grams per mole. Each gram weighs 0.501 grams. That would thus stand in for this. 2.34 grams of nitrogen would need to react with 0.501 grams of hydrogen to produce ammonia. 241=2 moles of nitrogen and 243=6 moles of hydrogen will be converted into 4 moles of ammonia. Nitrogen has a molar mass of 28 g/mol and hydrogen has a molar mass of 2 g/mol.
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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.
24. The density of silver at 20 °C is
10.5 g/cm³. What is the
volume of a 68-g bar of silver?
volume=6.5cm³
Explanation:
density= mass/ volume
volume= mass/ density
= 68/10.5
=6.5cm³