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

Какой газ составляет большую часть воздуха Земли?

1. AВодород
2. BУглекислый газ
3. CАзот
4. DКислород

What should a student always wear to protect the eyes when working with chemicals?

1. AContact lenses
2. BReading glasses
3. CSafety goggles
4. DSunglasses

How does increasing the concentration of a reactant in solution usually affect the reaction rate?

1. AThe reaction stops
2. BThe rate stays the same
3. CThe rate increases
4. DThe rate decreases

When mercury(II) oxide is heated, it reacts as 2HgO → 2Hg + O₂. What type of reaction is this?

1. ADecomposition
2. BSingle replacement
3. CCombustion
4. DSynthesis

A radioactive isotope has a half-life of 5 days. A sample starts with 80 g. How much is left after 10 days?

1. A20 g
2. B40 g
3. C0 g
4. D10 g

Why does keeping food in a refrigerator slow down spoilage?

1. ALower temperatures slow down chemical and microbial reactions
2. BLower temperatures raise the activation energy of every reaction
3. CCold air contains no oxygen
4. DCold temperatures add preservatives to the food

Alkanes follow the general formula CₙH₂ₙ₊₂. What is the formula of the alkane with 4 carbon atoms?

1. AC₄H₁₂
2. BC₄H₁₀
3. CC₄H₆
4. DC₄H₈

A liquid has a density of 1,2 g/mL. What is the mass of 250 mL of this liquid?

1. A300 g
2. B208 g
3. C30 g
4. D251,2 g