Робочий аркуш «Хімія для вступних іспитів на медсестринство» з відповідями

What is the half-life of a radioactive isotope?

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

What are enzymes?

1. ASugars that store energy in the liver
2. BFats that form most of the cell membrane
3. CBiological catalysts, usually proteins
4. DMinerals that build bone

Which gas is needed for a fuel to burn (combustion)?

1. ANitrogen
2. BOxygen
3. CCarbon dioxide
4. DHelium

What is the oxidation number of oxygen in most of its compounds?

1. A0
2. B−2
3. C+2
4. D−1

How many covalent bonds does a carbon atom usually form?

1. A1
2. B3
3. C4
4. D2

Which reacts more vigorously with water, potassium or sodium?

1. AThey react equally, because both are in group 1
2. BSodium, because it has fewer electron shells to shield its electron
3. CSodium, because its outer electron is farther from the nucleus
4. DPotassium, because its outer electron is farther from the nucleus

У рівнянні N₂ + 3H₂ → 2NH₃ скільки грамів аміаку (17 g/mol) можна отримати з 1 mol N₂ за надлишку водню?

1. A51 g
2. B28 g
3. C17 g
4. D34 g

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 falls, because less CO₂ means more H⁺ ions
4. DIt rises, because less CO₂ means fewer H⁺ ions