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

What does the octet rule state?

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

What is a dilute solution?

1. AOne in which the solute has reacted with the solvent
2. BOne with no solvent at all
3. COne with a large amount of solute in a little solvent
4. DOne with a small amount of solute in a lot of solvent

How many millilitres are in 1 litre?

1. A1000
2. B10
3. C100
4. D10,000

A reaction has ΔH = −890 kJ/mol. What does the negative sign tell you?

1. AThe reaction needs a catalyst
2. BThe reaction is at equilibrium
3. CThe reaction is endothermic
4. DThe reaction is exothermic

A gas mixture contains nitrogen at 600 mmHg, oxygen at 150 mmHg and other gases at 10 mmHg. What is the total pressure?

1. A600 mmHg
2. B253 mmHg
3. C750 mmHg
4. D760 mmHg

For the gas reaction N₂ + 3H₂ ⇌ 2NH₃, what is the effect of increasing the pressure?

1. AThe equilibrium shifts to the right, toward NH₃
2. BThe NH₃ breaks down completely
3. CThe equilibrium shifts to the left, toward N₂ and H₂
4. DThere is no effect on the equilibrium

Each C=O bond in carbon dioxide is polar, yet the CO₂ molecule is nonpolar. Why?

1. AThe molecule is linear, so the two bond dipoles cancel out
2. BCarbon has lone pairs that cancel the dipoles
3. CCarbon and oxygen have the same electronegativity
4. DThe bonds are ionic, not covalent

In the Bohr model, what happens when an electron drops from a higher energy level to a lower one?

1. AEnergy is absorbed from the surroundings
2. BEnergy is released, often as light
3. CThe atom gains a proton
4. DThe electron leaves the atom