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

Нейтральный атом имеет 11 протонов. Сколько у него электронов?

1. A12
2. B22
3. C11
4. D10

What range does the common pH scale cover?

1. A0 to 14
2. B−7 to +7
3. C0 to 100
4. D1 to 10

Какой тип реакции показан в реакции A + B → AB?

1. AЗамещение
2. BСоединение (синтез)
3. CРазложение
4. DГорение

Why does keeping food in a refrigerator slow down spoilage?

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

Glucose has the molecular formula C₆H₁₂O₆. What is its empirical formula?

1. ACHO
2. BCH₂O
3. CC₆H₁₂O₆
4. DC₂H₄O₂

On an energy diagram, the products are at a lower energy than the reactants. What kind of reaction is shown?

1. AEndothermic
2. BReversible only
3. CNuclear
4. DExothermic

Pepsin digests protein in the stomach at about pH 2, but it stops working once food moves into the small intestine, where the pH is higher. Why?

1. APepsin only works on fats in the small intestine
2. BThe change in pH alters the shape of pepsin's active site
3. CThe small intestine is too cold for any enzyme
4. DPepsin is used up completely in the stomach, just like a reactant

В реакции 2H₂ + O₂ → 2H₂O 4 г водорода (молярная масса 2 г/моль) реагируют с избытком кислорода. Какая масса воды образуется (молярная масса 18 г/моль)?

1. A4 г
2. B36 г
3. C18 г
4. D72 г