Q: What is the balanced chemical equation for the reaction of sodium with water?

$$2 \text{Na} (s) + 2 \text{H}_2\text{O} (l) \rightarrow 2 \text{NaOH} (aq) + \text{H}_2 (g)$$

Question 1

Which of the following best explains why potassium reacts more vigorously with water than lithium or sodium, as shown in the images?

Accepted Answer

Potassium's valence electron is farther from the nucleus, making it easier to lose and thus more reactive.

Question 2

What is the balanced chemical equation for the reaction of sodium with water?

Accepted Answer

$$2 	ext{Na} (s) + 2 	ext{H}_2	ext{O} (l) ightarrow 2 	ext{NaOH} (aq) + 	ext{H}_2 (g)$$

Question 3

When potassium reacts with water, which of the following products is NOT formed?

Accepted Answer

Oxygen gas

Question 4

Which trend is observed in the reactivity of alkali metals with water as you move down the group in the periodic table?

Accepted Answer

Reactivity increases

Question 5

If 0.10 mol of sodium reacts completely with excess water, how many moles of hydrogen gas are produced? Use the balanced equation: $$2 	ext{Na} (s) + 2 	ext{H}_2	ext{O} (l) ightarrow 2 	ext{NaOH} (aq) + 	ext{H}_2 (g)$$

Accepted Answer

0.05 mol

Question 6

Which of the following best describes the type of reaction occurring when lithium reacts with water?

Accepted Answer

Single displacement (single replacement)

Question 7

A student observes that the reaction of potassium with water produces a lilac flame and is much more vigorous than sodium. What is the best explanation for this observation?

Accepted Answer

Potassium has a lower ionization energy than sodium.

Question 8

Which safety precaution is most important when demonstrating the reaction of alkali metals with water in a laboratory?

Accepted Answer

Wear safety goggles and use a safety shield to protect from splashing and possible explosions.

Question 9

Which of the following statements about the products of alkali metal reactions with water is correct?

Accepted Answer

The reaction produces a metal hydroxide and hydrogen gas.

Question 10

If 4.60 g of sodium metal reacts with excess water, what mass of sodium hydroxide is produced? (Molar mass of Na = 23.0 g/mol, NaOH = 40.0 g/mol) Use the equation: $$2 	ext{Na} (s) + 2 	ext{H}_2	ext{O} (l) ightarrow 2 	ext{NaOH} (aq) + 	ext{H}_2 (g)$$

Accepted Answer

8.00 g

Chemical Reactions and Chemical Quantities: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards