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

Which element makes up the largest share of the human body by mass?

1. ACarbon
2. BOxygen
3. CHydrogen
4. DNitrogen

In a chemical reaction, what is the limiting reactant?

1. AThe catalyst that controls the speed
2. BThe reactant that is left over at the end
3. CThe reactant that runs out first and stops the reaction
4. DThe reactant with the largest mass

According to collision theory, what must happen for particles to react?

1. AThey must have the same mass
2. BThey must stay completely still next to each other
3. CThey must both be in the solid state at the same time
4. DThey must collide with enough energy and the right orientation

To which family of organic compounds does ethanol, C₂H₅OH, belong?

1. ACarboxylic acids
2. BAlcohols
3. CAlkanes
4. DEsters

Why does the vapour pressure of a liquid increase as it is heated?

1. AThe attractions between the molecules become stronger
2. BThe molecules become heavier and press harder on the surface
3. CThe liquid's volume decreases and squeezes out vapour
4. DMore molecules have enough energy to escape into the gas phase

On an energy diagram, the products are at a lower energy than the reactants. What kind of reaction is shown?

1. AEndothermic
2. BReversible only
3. CNuclear
4. DExothermic

What is the percentage by mass of nitrogen in ammonium nitrate, NH₄NO₃ (N = 14, H = 1, O = 16; molar mass 80 g/mol)?

1. A60%
2. B35%
3. C17,5%
4. D28%

Vitamin C is water-soluble and vitamin D is fat-soluble. What does this suggest about their molecules?

1. ABoth are equally polar
2. BVitamin C is nonpolar, while vitamin D is strongly polar
3. CVitamin C is polar, while vitamin D is mostly nonpolar
4. DBoth are ionic compounds