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

Как называется переход непосредственно из твёрдого состояния в газообразное?

1. AПлавление
2. BКонденсация
3. CДесублимация
4. DСублимация

What is a solution?

1. AA pure compound made of two elements
2. BA solid that has been melted
3. CA mixture that is the same throughout (homogeneous)
4. DA mixture in which particles settle out on standing

Which unit is commonly used for the density of a liquid?

1. Ag·mL
2. BmL/g
3. Cg/mL
4. Dkg

How does evaporation differ from boiling?

1. AEvaporation needs a higher temperature than boiling
2. BEvaporation happens throughout the liquid at a set temperature; boiling happens only at the surface
3. CEvaporation produces a solid, while boiling produces a gas
4. DEvaporation happens only at the surface and at any temperature; boiling happens throughout the liquid at a set temperature

A reaction has a theoretical yield of 20 g, but only 15 g of product is collected. What is the percent yield?

1. A133%
2. B25%
3. C5%
4. D75%

What is the normal boiling point of a liquid?

1. AThe temperature at which its particles stop moving
2. BThe temperature at which its density is greatest
3. CThe temperature at which its vapour pressure equals 1 atmosphere
4. DThe temperature at which it first starts to evaporate

Orange bromine water is shaken with two hydrocarbons. With hexene it turns colourless; with hexane it stays orange. What does this show?

1. AHexene is an alcohol and hexane is an acid
2. BHexene contains a C=C double bond; hexane does not
3. CHexane contains a C=C double bond; hexene does not
4. DBoth contain double bonds, but hexane reacts more slowly

Почему масло не растворяется в воде?

1. AМасло реагирует с водой, образуя твёрдое вещество
2. BВода слишком плотная, чтобы смешиваться с чем-либо
3. CМолекулы масла — заряженные ионы
4. DМасло неполярно, а вода полярна, и «подобное растворяется в подобном»