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

Which is a sign that a chemical reaction may have taken place?

1. AA block of wax melts when it is heated
2. BSugar dissolves completely when stirred into water
3. CWater freezes into ice when put in a freezer
4. DA gas is produced when two liquids are mixed

Какая частица атома почти не имеет массы по сравнению с остальными?

1. AЭлектрон
2. BЯдро в целом
3. CПротон
4. DНейтрон

What does the octet rule state?

1. AEvery stable atom has exactly 8 protons in its nucleus
2. BEvery stable molecule contains exactly 8 atoms
3. CAn atom can form a maximum of 8 covalent bonds
4. DAtoms tend to gain, lose or share electrons to get 8 outer electrons

Which statement describes a saturated fat?

1. AIt contains no carbon atoms
2. BIt is always liquid at room temperature
3. CIts fatty acid chains have no carbon–carbon double bonds
4. DIts fatty acid chains have many carbon–carbon double bonds

When the diaphragm contracts and the chest cavity gets bigger, what happens to the air pressure inside the lungs?

1. AIt falls, so air flows in
2. BIt falls, so air flows out
3. CIt does not change
4. DIt rises, so air flows in

A piece of metal has a density of 8 g/cm³ and a volume of 5 cm³. What is its mass?

1. A13 g
2. B0,625 g
3. C1,6 g
4. D40 g

A catalyst is added to an exothermic reaction. How does the energy diagram change?

1. AThe reaction becomes endothermic
2. BThe reactants start at a higher energy
3. CThe products end up at a lower energy, so more heat is released
4. DThe peak is lower, but the energy of reactants and products stays the same

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

1. A150 мл
2. B100 мл
3. C900 мл
4. D50 мл