Question 1

Which of the following best describes a gas evolution equation in chemistry?

Accepted Answer

A molecular equation that results in the creation of CO$$_2$$ gas.

Question 2

Given the reaction: $$Na_2CO_3 (aq) + 2 HCl (aq) \rightarrow 2 NaCl (aq) + H_2CO_3 (aq)$$, what is the gas evolved?

Accepted Answer

CO$$_2$$

Question 3

In the gas evolution reaction between $$KHCO_3$$ and $$HCl$$, which of the following is the correct set of products?

Accepted Answer

KCl and H$$_2CO$_3$$

Question 4

What is the correct balanced molecular equation for the reaction between $$Na_2CO_3$$ and $$HCl$$?

Accepted Answer

$$Na_2CO_3 (aq) + 2 HCl (aq) \rightarrow 2 NaCl (aq) + H_2CO_3 (aq)$$

Question 5

When $$H_2CO_3 is $$formed in a gas evolution reaction, what typically happens next?

Accepted Answer

$$H_2CO_3$$ decomposes into $$CO_2$$ and $$H_2O$$

Question 6

Which step is necessary to predict the products of a gas evolution reaction?

Accepted Answer

Break up the reactants into their ionic forms

Question 7

In the reaction $$KHCO_3 (aq) + $$HCl (aq) \rightarrow KCl (aq) + H_2CO_3 (aq)$$, which ion swaps partners during the reaction?

Accepted Answer

K$$^+$$ and H$$^+$$

Question 8

Why is it important to balance the charges when swapping ionic partners in a gas evolution reaction?

Accepted Answer

To ensure the products are electrically neutral

Question 9

Which of the following is the correct net ionic equation for the reaction between $$Na_2CO_3$$ and $$HCl$$?

Accepted Answer

$$CO_3$$^{2-} (aq) + 2 H^+ (aq) \rightarrow H_2CO_3 (aq)$$

Question 10

A student mixes $$Na_2CO_3$$ and $$HCl in a $$beaker and observes bubbling. What is the most likely cause of this observation?

Accepted Answer

Evolution of CO$$_2$$ gas from the decomposition of $$H_2CO_3$$

Question 11

Which of the following is a correct application of the gas evolution reaction in a real-world scenario?

Accepted Answer

Using baking soda ($$NaHCO_3) $$and vinegar ($$CH_3COOH) to $$produce CO$$_2$$ for inflating balloons

Question 12

If you start with 0.5 mol of $$Na_2CO_3$$ and excess $$HCl$$, how many moles of $$CO_2$$ gas will be produced?

Accepted Answer

0.5 mol

Question 13

Which of the following is the correct sequence of steps for predicting the products of a gas evolution reaction?

Accepted Answer

Break up reactants, swap ionic partners, identify the gas, balance the equation

Question 14

Which of the following ions is responsible for the evolution of gas in the reaction between $$Na_2CO_3$$ and $$HCl$$?

Accepted Answer

CO$$_3$$^{2-}$$

Question 15

A student incorrectly predicts that mixing $$KHCO_3$$ and $$HCl$$ will produce $$KOH$$ and $$HCl. $$What is the error in their reasoning?

Accepted Answer

They did not swap the correct ionic partners based on charge

Question 16

Which of the following best explains why $$H_2CO_3 is $$rarely isolated in gas evolution reactions?

Accepted Answer

$$H_2CO_3 is $$unstable and quickly decomposes into $$CO_2$$ and $$H_2O$$

Question 17

In a gas evolution reaction, why is it important to use the correct stoichiometric coefficients?

Accepted Answer

To ensure the law of conservation of mass is obeyed

Question 18

Which of the following is a common misconception when predicting the products of a gas evolution reaction?

Accepted Answer

Assuming the gas is produced directly from the reactants without forming an intermediate

Question 19

A patient is given an antacid containing $$NaHCO_3 to $$neutralize stomach acid ($$HCl). $$What gas is produced in this reaction?

Accepted Answer

CO$$_2$$

Gas Evolution Equations in Chemical Reactions

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