Химия для вступительных экзаменов на сестринские программы: лист заданий с ответами

About what percentage of dry air is oxygen?

1. A78%
2. B50%
3. C21%
4. D1%

What is a cation?

1. AA molecule with no charge
2. BA neutral atom
3. CA negatively charged ion
4. DA positively charged ion

A blown-up balloon is put in a freezer. What happens to its volume?

1. AIt increases
2. BIt decreases
3. CThe balloon bursts
4. DIt stays exactly the same

At STP (0 °C and 1 atm), what volume does 1 mole of an ideal gas occupy?

1. A6,02 L
2. B273 L
3. C1,0 L
4. D22,4 L

What is the formula of sodium sulfate, made from Na⁺ and SO₄²⁻ ions?

1. ANa(SO₄)₂
2. BNa₄SO₂
3. CNa₂SO₄
4. DNaSO₄

Rubbing alcohol evaporates faster than water at room temperature. What does this suggest?

1. AIt has a higher boiling point than water
2. BIts intermolecular forces are stronger than water's
3. CIts molecules are heavier than water molecules
4. DIts intermolecular forces are weaker than water's

A reaction at equilibrium has a very large equilibrium constant (K much greater than 1). What does this tell you?

1. AThe reaction cannot reach equilibrium
2. BThe reaction is very fast
3. CAt equilibrium, the mixture contains mostly reactants
4. DAt equilibrium, the mixture contains mostly products

In the fission reaction ²³⁵U + ¹n → ¹⁴¹Ba + ⁹²Kr + ? ¹n, how many neutrons are released?

1. A3
2. B1
3. C2
4. D4