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

What is a precipitate?

1. AA liquid that forms when a solid melts
2. BA gas that bubbles out when two solutions are mixed
3. CA substance that speeds up a reaction
4. DAn insoluble solid that forms when two solutions react

Which quantity is the same for 1 mole of any substance?

1. AThe number of particles
2. BThe number of atoms per molecule
3. CThe mass in grams
4. DThe volume as a liquid

What is gamma radiation?

1. AA slow-moving electron
2. BA stream of helium nuclei with a positive charge
3. CA fast stream of protons from the nucleus
4. DHigh-energy electromagnetic radiation with no mass or charge

A reaction has a theoretical yield of 20 g, but only 15 g of product is collected. What is the percent yield?

1. A5%
2. B133%
3. C25%
4. D75%

In 2KClO₃ → 2KCl + 3O₂, how many moles of O₂ form from 4 mol of KClO₃?

1. A8 mol
2. B3 mol
3. C4 mol
4. D6 mol

Сколько молей содержится в 88 г углекислого газа (молярная масса 44 г/моль)?

1. A44 моль
2. B3872 моль
3. C0,5 моль
4. D2 моль

Какой объём 6 М исходного раствора нужен для приготовления 300 мл 2 М раствора?

1. A100 мл
2. B150 мл
3. C900 мл
4. D50 мл

CO₂ in blood forms carbonic acid: CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻. An anxious patient hyperventilates and breathes off extra CO₂. What happens to blood pH?

1. AIt falls, because oxygen is an acid
2. BIt stays exactly 7,40, because CO₂ does not affect pH
3. CIt rises, because less CO₂ means fewer H⁺ ions
4. DIt falls, because less CO₂ means more H⁺ ions