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

Which of these is a polyatomic ion?

1. AOxide, O²⁻
2. BSodium, Na⁺
3. CChloride, Cl⁻
4. DSulfate, SO₄²⁻

В какой группе находятся благородные газы, например гелий и неон?

1. AВ группе 2
2. BВ группе 1
3. CВ группе 18
4. DВ группе 17

Plants absorb energy from sunlight during photosynthesis. How is photosynthesis classified?

1. AEndothermic
2. BExothermic
3. CNeutralisation
4. DNuclear

What is the name of the compound CaCO₃?

1. ACalcium carbonate
2. BCalcium carbide
3. CCalcium oxide
4. DCarbon calcium trioxide

Как в целом изменяется атомный радиус при движении слева направо по периоду?

1. AСначала удваивается, затем уменьшается вдвое
2. BОстаётся в точности прежним
3. CУменьшается
4. DУвеличивается

Water has a high specific heat capacity. How does this help the human body?

1. AIt allows oxygen to dissolve in water more easily
2. BIt makes the blood more acidic
3. CIt helps keep body temperature stable
4. DIt makes water a poor solvent for salts

Why are the radioactive tracers used for medical imaging usually chosen to have short half-lives?

1. AThey emit only alpha particles, which are harmless inside the body
2. BThey give a strong signal for imaging but leave the body's tissues exposed only briefly
3. CShort half-life isotopes are not radioactive
4. DThey stay active for many years, so a single dose can be used for every future scan

Gently heating DNA separates its two strands, but each strand stays in one piece. Why?

1. AThe strands are held together by weak hydrogen bonds, while each strand's backbone is covalent
2. BHeat converts DNA into a protein
3. CThe two strands are joined by ionic bonds that melt first
4. DEach strand is held together by hydrogen bonds, while the two strands are joined by covalent bonds