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

What is an acid–base indicator?

1. AA gas given off by acids
2. BA substance that neutralises every acid
3. CA device that measures temperature
4. DA substance that changes colour depending on pH

Which property is typical of bases?

1. AThey taste sour
2. BThey feel slippery
3. CThey turn blue litmus red
4. DThey have a pH below 7

Which electrons take part in chemical bonding?

1. AThe valence (outermost) electrons
2. BOnly the electrons in the first shell
3. CAll electrons take part equally
4. DThe electrons closest to the nucleus

In 2KClO₃ → 2KCl + 3O₂, how many moles of O₂ form from 4 mol of KClO₃?

1. A6 mol
2. B3 mol
3. C4 mol
4. D8 mol

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

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

Which element has the most metallic character?

1. AChlorine (Cl)
2. BCaesium (Cs)
3. CSodium (Na)
4. DAluminium (Al)

Pepsin digests protein in the stomach at about pH 2, but it stops working once food moves into the small intestine, where the pH is higher. Why?

1. AThe change in pH alters the shape of pepsin's active site
2. BPepsin only works on fats in the small intestine
3. CPepsin is used up completely in the stomach, just like a reactant
4. DThe small intestine is too cold for any enzyme

Zinc reacts as Zn + 2HCl → ZnCl₂ + H₂. What mass of zinc (65 g/mol) reacts completely with 50 mL of 2 M HCl?

1. A6,5 g
2. B65 g
3. C1,63 g
4. D3,25 g