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

Что такое ион?

1. AАтом или группа атомов с электрическим зарядом
2. BАтом, у которого в ядре больше нейтронов, чем у других атомов
3. CЧастица без электронов
4. DМолекула из двух одинаковых атомов

In a chemical reaction, what is the limiting reactant?

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

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

1. AHydrogen
2. BNitrogen
3. COxygen
4. DCarbon

A radioactive isotope has a half-life of 5 days. A sample starts with 80 g. How much is left after 10 days?

1. A40 g
2. B0 g
3. C10 g
4. D20 g

What are London dispersion forces?

1. AStrong bonds formed by transferring electrons
2. BForces that hold protons together in the nucleus
3. CWeak, temporary attractions caused by shifting electrons in molecules
4. DAttractions between a hydrogen atom and a metal ion

How does a mixture of iron filings and sulfur powder differ from the compound iron sulfide?

1. AThe mixture can be separated physically, for example with a magnet
2. BThe compound keeps the magnetic properties of iron
3. CThe mixture has a fixed ratio of iron to sulfur
4. DThe mixture is formed by a chemical reaction between the two elements

A reaction should produce 2 mol of a product with a molar mass of 30 g/mol, but only 48 g is collected. What is the percent yield?

1. A80%
2. B125%
3. C60%
4. D48%

100 mL of 1 M NaCl is mixed with 100 mL of 3 M NaCl. What is the concentration of the mixture?

1. A3 M
2. B2 M
3. C4 M
4. D1,5 M