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

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

1. AEndothermic
2. BNeutralisation
3. CExothermic
4. DNuclear

What is the half-life of a radioactive isotope?

1. AThe time taken for the mass of a sample to double in size
2. BHalf the number of protons in the nucleus
3. CThe time taken for half of the radioactive atoms in a sample to decay
4. DHalf the time it takes for all the atoms to decay

Какой тип связи образуется, когда атомы обобществляют электроны?

1. AМеталлическая связь
2. BЯдерная связь
3. CКовалентная связь
4. DИонная связь

Nitric acid (HNO₃) reacts with potassium hydroxide (KOH). Which salt forms?

1. APotassium hydride, KH
2. BPotassium nitrite, KNO₂
3. CPotassium nitrate, KNO₃
4. DNitrogen hydroxide, NOH

A red blood cell is placed in a concentrated (hypertonic) salt solution. What happens?

1. AWater enters the cell, which swells and may burst
2. BWater leaves the cell, which shrinks
3. CThe cell stays the same size and shape
4. DSalt leaves the cell, which swells

Why does ice float on liquid water?

1. AIce is denser than liquid water
2. BIce is less dense than liquid water
3. CIce has a higher mass than the same volume of water
4. DIce contains trapped air from the freezer

Na⁺, Mg²⁺, F⁻ and O²⁻ all have 10 electrons. Which ion is the largest?

1. AO²⁻
2. BF⁻
3. CNa⁺
4. DMg²⁺

Ethanol (CH₃CH₂OH) and dimethyl ether (CH₃OCH₃) have the same formula, C₂H₆O, but ethanol boils at a much higher temperature. Why?

1. AEthanol has an O–H group, so its molecules form hydrogen bonds with each other
2. BDimethyl ether is ionic and ethanol is covalent
3. CEthanol molecules are heavier than dimethyl ether molecules
4. DEthanol has more carbon atoms