Answer:
pH = 11.9
Explanation:
First, we determine the number of OH⁻ moles dissolved:
80% of Ca(OH)₂ is dissolved:
0.0005 mol * 80/100 = 4x10⁻⁴ mol Ca(OH)₂There are two OH⁻ moles per Ca(OH)₂ mol:
4x10⁻⁴ * 2 = 8x10⁻⁴ mol OH⁻Now we can calculate the molar concentration of OH⁻ (moles/L):
100 cm³ = 100 mL100 mL ⇒ 100/1000 = 0.1 L[OH⁻] = 8x10⁻⁴ mol / 0.1 L = 8x10⁻³ MThen we calculate the pOH of the solution:
pOH = -log[OH⁻] = -log(8x10⁻³ M) = 2.10Finally, we can calculate the pH of the solution using the equation
pH + pOH = 14pH = 14 - pOH = 14 -2.10pH = 11.9John is performing an experiment in which a solution alternates between a clear color and a bluish-purple color at a regular time interval. He observes that the time interval between color changes is 30 seconds (s). Sally replicates the experiment with the same solution, but at a temperature that is 10 degrees Celsius (°C) higher. What is the most likely time interval between color changes at this higher temperature? *
Answer:
15 sec
Explanation:
Which formula equation shows a reversible reaction? 2 Upper N a + Upper F Subscript 2 Baseline right arrow 2 Upper N a Upper F. Upper C a Upper C Upper O Subscript 3 Baseline right arrow Upper C a Upper O + Upper C Upper O Subscript 2. Upper N Upper H Subscript 4 Baseline Upper C l (s) double-pointed arrow Upper N Upper H Subscript 3 Baseline (g) + Upper H Upper C l (g). 2 Upper H Subscript 2 Baseline Upper O Subscript 2 Baseline (a q) right arrow with n above it 2 Upper H Subscript 2 Baseline Upper O (l) + Upper O Subscript 2 Baseline (g).
Answer:
NH₄Cl ⇄ NH₃ + HCl
Explanation:
The formula equation shows a reversible reaction is:
NH₄Cl(s) ⇄ NH₃(g) + HCl(g)
Classification of reactions according to their reversibilityReversible reactions: They occur in both senses, as denoted by a double arrow.Irreversible reactions: They occur in one sense, as denoted by a single arrow.Let's consider which formula equation shows a reversible reaction.
2 Na + F₂ ⇒ 2 NaFThe single arrow indicates that this is an irreversible reaction.
CaCO₃ ⇒ CaO + CO₂The single arrow indicates that this is an irreversible reaction.
NH₄Cl(s) ⇄ NH₃(g) + HCl(g)The double arrow indicates that this is a reversible reaction.
2 H₂O₂(aq) ⇒ 2 H₂O(l) + O₂(g)The single arrow indicates that this is an irreversible reaction.
The formula equation shows a reversible reaction is:
NH₄Cl(s) ⇄ NH₃(g) + HCl(g)
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What happens when A mixture of ammonia and oxygen is passed over platinum gauze heated to 800°C .
Answer:
The mixture forms nitrogen oxide and water upon reaction. However, 800 degree Celsius falls at higher limit of the process condition. It being an exothermic reaction, the reaction rate will be on the lower side than average.
3. How many moles are in 1.49 x 1023 molecules of iodine?
Answer:
The answer is 0.25 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{1.49 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{1.49}{6.02} \\ = 0.247508305...[/tex]
We have the final answer as
0.25 molesHope this helps you
If a radiation source has a wavelength of 4.76 x 10-6 m, then what is its frequency?
Answer: 6.3 * 10^15
Explanation:
wavelength = speed of light / frequency
so rewriting the equation gives frequency = speed of light / wavelength
so 3.0 *10^10 / 4.76 * 10^-6 = 6.3 * 10^15
How does nano frabic work
Answer:
Nano silver is woven into fabric to give it anti-bacterial properties.
Explanation:
Helps by fending off the bacteria that make those clothes smell after you sweat. Nano-titanium dioxide adds sun protection to clothing just as it does in sunscreen. The use of nanoparticles to achieve fresh-smelling clothes and UV protection may not be safe.
formal units are formed by?
Answer:
However, when formal units are used to measure length, the measurement can usually be read from a scale on a ruler or tape, which shows units of a particular size. Unit iteration involves knowledge of repeatedly placing identical tightly packing units so that there are no overlaps or gaps.
Explanation:
Predict: Note the type of reaction you expect for
the sole reactant Na2CO3.
a. single replacement
b. double replacement
c. combustion (and synthesis)
d. synthesis
e. decomposition
Answer:
double replacement
Explanation:
Answer:
It is indeed double replacement
Explanation:
Darwin told us that science:
saves lives
Answer:yup!!
Explanation:
1. Which of the following is not a major classification for elements in the periodic table?
O a. metals
O b. metalloids
O c. nonmetals
O d. noble gases
Answer:
Noble gases
Explanation:
A student observes that a popcorn kernel has a hard coat. He places the kernel in a moist paper towel and observes it for several days. He notices that the coat splits and a small root emerges. He concludes that
Answer: Water inside the seed coat creating a pushing force, breaking the seed coat.
Explanation:
Seed germination can be defined as the process by which a new plant emerge out from a seed. The radicle is the first emerging part from a seed and it develops into a root and the plumule is the second emerging part and it develops into a shoot. The light, water, adequate temperature, and soil are the factors that are necessary for seed germination.
According to a given situation, the popcorn kernel will receive the moisture necessary for the germination process, the water will imbibe into the seed coat creating pressure inside the seed and which will cause the seed coat to break and the new plant parts or seedling will emerge out of the seed coat.
True or False;
aa is faster moving lava than pahoehoe?
Answer:
It is false :l
Explanation:
Pahoehoe is a smooth and continuous lava crust. Pahoehoe forms when the effusion rate is low and consequently the velocity of lava flow is slow. Pahoehoe lava flow is usually at least 10 times slower than typical aa lava flow.
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An oxide named CrO. So the salt of chromium has the corresponding valence
Answer:
this question doesnt make any sene
Explanation:
Redi placed pieces of meat in several jars. He divided the jars into two groups. He covered the first group of jars with fine cloth. He left the second group of jars uncovered. Redi observed the jars for several days. He saw flies on the cloth of the covered jars, and he saw flies laying eggs on the meat in the uncovered jars. Maggots appeared only on the meat in the group of jars left uncovered.
What is the question in Redi's experiment?
What is the independent (test) variable?
What is the dependent (outcome) variable?
Write a hypothesis for Redi's experiment
Answer:
Experiment Question, Independent & Dependent Variable, Null & Alternate Hypothesis
Explanation:
Experiment Question : Whether fine cloth coverage over chicken jars effect flies & their eggs in ambience ?
Independent Variable : The causal variable, ie cloth cover existence on the chicken jar
Dependent Variable : The resultant variable, ie presence of flies & their eggs near jar, meat
Null Hypothesis [H0] : Cloth cover on chicken jar doesn't effects flies' & eggs' presence around jar, chicken.
Alternate Hypothesis [H1] : Cloth cover on chicken jar effects flies' & eggs' presence around jar, chicken.
Which bond is a very strong dipole-dipole force?
A. A covalent bond
B. An ionic bond
C. A hydrogen bond
D. A metallic bond
Answer : C. A hydrogen bond
Explanation:
Answer:
A. covalent bond
Explanation:
dipole-dipole interaction results from difference in electronegativity , eg H-F where Fluorine has strong electronegativity but Hydrogen has less electronegativity. hence the bond has dipole moment towards F atom.
Does Rubidium (Rb) have high or low electronegativity?
Answer:
high
Explanation:
In a solution, what term is given to the liquid?
Answer: solvent
solvent is A solvent is usually a liquid
Answer: Solvent
Explanation: Everything that dissolves in water and the things which dissolve are called solutes and the liquid in which they dissolve in is called a solvent to form a solution.
Can someone help me please will give BRAINIEST
Complete the conversions for the following temperature measurements:
55.3C=_____K
255K=_____C
447K=_____C
-14C=_____K
Answer:
55.3 = 328.45k
255 = 18.15°c
447 = 173.85°c
-14 = 14k
What determines the appearance of the moon from earth?
To solve this we must be knowing each and every concept related to satellite. Therefore, moon phases and moon placements have a role the appearance of the moon from earth.
What is satellite?Any object that circles a planet in a curved route is considered a satellite. There are several man-made (manufactured) satellites, most of which are closer to Earth than the moon, which is Earth's original natural satellite.
We must revisit our buddy Newton in order to comprehend why satellites move in this manner. Gravity, according to Newton, is a force that unites all of the universe's objects. Moon phases and moon placements have a role in determining this. The only major factor affecting the Moon's phase is where it is in relation to Earth and the Sun.
Therefore, moon phases and moon placements have a role the appearance of the moon from earth.
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A sealed can of soda contain a pressure of 1.15 atm at 23°C. What is the new pressure at 79 °C? Report your answer to the hundredths place (two decimal places) You do NOT need units in your answer
Answer:
P₂ = 1.37
Explanation:
Given data:
Initial pressure = 1.15 atm
Initial temperature = 23°C (23+273= 296 K)
Final pressure = ?
Final temperature = 79°C (79+273=352 K)
Solution:
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
Now we will put the values in formula:
1.15 atm / 296 K = P₂/352 K
P₂ = 1.15 atm × 352 K / 296 K
P₂ = 404.8 atm. K /296 K
P₂ = 1.37 atm
Help please !
A
B
C
D
Answer:
the answer is letter B. the entropy
If a neutral compound is composed of carbon and hydrogen and you know that it has exactly 2 carbons connected by a double bond, how many hydrogens will the compound have?
Answer: 4 hydrogens
Explanation:
This is what the structure will look like C=C. Remember that it's important that all structures have a complete octet. As it looks right now each carbon is sharing 4 valence electrons so each needs 2 more bonds to hydrogen complete its octet.
Answer: 4 hydrogens
Explanation:
Sodium metal reacts violently with water and chlorine is a toxic gas, yet we eat sodium chloride. Why is this possible? Select one: a. The properties of compounds are different from the properties of the elements that form the compounds.
b. The properties of compounds are identical to the properties of the elements that form the compounds, and we should not eat sodium chloride because it is toxic.
c. The physical properties of compounds are different from the physical properties of the elements that form the compounds, but the chemical properties of the elements and compound are the same.
d. The chemical properties of compounds are different from the chemical properties of the elements that form the compounds, but the physical properties of the elements and compound are the same.
Answer:
The properties of compounds are different from the properties of the elements that form the compounds.
Explanation:
When elements form compounds, their properties are significantly modified. The physical and chemical properties of compounds and that of the elements that compose them are significantly different.
The introduction of chemical bonds between different atoms in compounds make the compounds to differ from elements where the atoms are bonded to atoms of the same element.
how many significant figures are in 0.00970 g?
Answer:
3
Explanation:
begining 0's are never significant
all numbers 1-9 are always significant
ending 0's are only significant when there is
a decimal.
is xenon a metal and is Beryllium a metal
Answer:
No and yes
Explanation:
Xenon is a noble gas and beryllium is a metal
Answer: no and yes i also agree
Xenon is a noble gas and Beryllium a metal
Explanation:
when a substance melts the kinetic energy
A Decreases then increase
B Decrease
C Stays the same
D Increase
Answer:
C stays The same.
Is the answer.
400 liters of a certain gas is collected at STP. What will the volume be at 273 C and 190 torr pressure?
Answer:
2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at STP? STP is a common abbreviation for "standard temperature and pressure." You have to recognize that five values are given in the problem and the sixth is an x. Also ... 273 1. A gas has a volume of 800.0 mL at minus 23.00 °C and 300.0 torr.
Explanation:
please answer willl give brainlist !!! Name the noble gases. What are the common properties between them?
Answer: Other characteristics of the noble gases are that they all conduct electricity, fluoresce, are odorless and colorless, and are used in many conditions when a stable element is needed to maintain a safe and constant environment. This chemical series contains helium, neon, argon, krypton, xenon, and radon.
Helpppppp!!!!! It’s due today
URGENT!!!!!
Answer:
Explanation:
2. a [CO3 2-][H3O+] / [H2O][HCO3-
b. [H2PO4-][H3O+]/[H3PO4][H2O]
Non examples of chemical change
List some please
Answer:
Crushing a can.
Melting an ice cube.
Boiling water.
Mixing sand and water.
Breaking a glass.
Dissolving sugar and water.
Shredding paper.
Chopping wood.
Some non-examples of the chemical reaction should be boiling water, glass breaking out, etc.
Chemical reaction
It is a process where one or more substances that we know as reactants should be transformed into one or more distinct substances that we know as products. Here the substances should be treated as the elements of chemicals or the compounds.Chemical reactions are an integral part of technology, culture, and indeed of life itself. Burning fuels, smelting iron, making glass and pottery, brewing beer, and making wine and cheese are among many examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, in the atmosphere and oceans, and in a vast array of complicated processes that occur in all living systems.Therefore, Some non-examples of the chemical reaction should be boiling water, glass breaking out, etc.
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