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3 years ago

Can someone me Help please

Chemistry

1 answer:

soldier1979 [14.2K]3 years ago

8 0

Independent would be the amount of sugar given and the dependent would be the amount of cavities

Scientists have control groups so they can have evidence to show the difference between that one and the experimental ones.

And the independent variable is the one that changes because with out it changing you wouldn't get different results.

I could be wrong tho sorryyy! but i hope this helps

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What Is the molar mass of H2O

r-ruslan [8.4K]

Answer:

18.01528 g/mol

Explanation:

5 0

3 years ago

Read 2 more answers

Ammonia (NH3) reacts with oxygen to form nitric oxide (NO) and water vapor: 4NH3 + 502 4NO + 6H2O b) When 20.0 g NH3 and 50.0 g

Solnce55 [7]

Answer: a) . Ammonia is the limiting reagent

b. Oxygen is left over and 0.1375 g of oxygen is left over.

c. The theoretical yield of $NO$ is 35.29 g.

d. The theoretical yield of $H_2O$ is 31.74 g.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

For $NH_3$

Given mass of ammonia = 20.0 g

Molar mass of ammonia = 17.031 g/mol

Putting values in equation 1, we get:

$\text{Moles of ammonia}=\frac{20.0g}{17.031g/mol}=1.17mol$

For $O_2$

Given mass of oxygen gas = 50.0 g

Molar mass of oxygen gas = 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of oxygen gas}=\frac{50.0g}{32g/mol}=1.6mol$

The chemical equation for the reaction is

$4NH_3+5O_2\rightarrow 4NO+6H_2O$

By Stoichiometry of the reaction:

4 moles of ammonia reacts with = 5 moles of oxygen

So 1.17 moles of ammonia will react with = $\frac{5}{4}\times 1.17=1.4625mol$ of oxygen

As, given amount of oxygen is more than the required amount. So, it is considered as an excess reagent and (1.6-1.4625)= 0.1375 g of oxygen is left unreacted.

Thus ammonia is considered as a limiting reagent because it limits the formation of product.

1. By Stoichiometry of the reaction:

4 moles of ammonia produces = 4 moles of $NO$

1.17 moles of ammonia will produce = $\frac{4}{4}\times 1.17=1.17moles$ of $NO$

Mass of $NO=moles\times {\text{Molar Mass}}=1.17\times 30=35.29g$

Thus Theoretical yield of $NO$ is 35.29 grams.

2. By Stoichiometry of the reaction:

4 moles of ammonia produces = 6 moles of $H_2O$

1.2 moles of ammonia will produce = $\frac{6}{4}\times 1.2=1.8moles$ of $H_2O$

Mass of $H_2O=moles\times {\text{Molar Mass}}=1.8\times 18.015=31.74g$ $H_2O$

Thus Theoretical yield of $H_2O$ is 31.74 grams.

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3 years ago

Diamonds and graphite are both made of carbon atoms. Why do they have different properties?

AysviL [449]

Answer: Graphite and Diamond are different because they have different structures. Both have Giant Covalent Structures resulting in very high melting temperatures.
Explanation: each carbon atom in Diamond has 4 covalent bonds with other Carbons, making it extremely strong and hard.

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3 years ago

Which one of the following statements is true? The internal energy of a system will not chage if there is no heat exchange betwe

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Answer:

The statement d) is true: The entropy of the universe is always increased in a spontaneous process.

Explanation:

a), b), c) and e) are false.

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b) Breaking a bond will always require energy, whereas forming a bond releases energy. Therefore, if more bonds are broken than formed, the enthalpy of a reaction will be positive.

c) The second law of thermodynamics states that the entropy of the universe increases in a spon taneous process and remains unchanged in an equilibrium process. Therefore, the entropy of the universe is not always constant.

d) True.

e) According to the Gibbs equation, if ΔH is negative and ΔS is negative, then ΔG will be negative only when TΔS is smaller in magnitude than ΔH. This condition is met when T is small.

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4 years ago

If the salt created from the reaction of a strong acid and a weak base is added to a solution, what will happen to the solution

hoa [83]

Answer:

See Explanation

Explanation:

When a salt is dissolved in water, the solution could be acidic, basic or neutral depending on the nature of acid and base from which the salt was formed.

When a salt is formed from a strong acid and a weak base, the salt solution is acidic.

For instance, NH4Cl is a salt formed from NH3 which is a weak base and HCl which is a strong acid. The salt hydrolyses as follows;

NH4^+(aq) + H2O(l) ------> H3O^+(aq) + NH3(aq)

Hence an acidic solution is formed.

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3 years ago