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

What is a solution?

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

What is the name for the attraction of water molecules to each other?

1. AOsmosis
2. BCohesion
3. CAdhesion
4. DDiffusion

What do the letters STP stand for in gas chemistry?

1. ASpecific temperature and particles
2. BStable temperature point
3. CStandard time and pressure
4. DStandard temperature and pressure

How many covalent bonds does a carbon atom usually form?

1. A4
2. B3
3. C1
4. D2

Why must temperatures be in kelvin in gas law calculations?

1. ACelsius can only be used for liquids
2. BGas volume and pressure are proportional to the absolute temperature
3. CThe kelvin scale has smaller degrees, which gives more precise answers
4. DKelvin values are always below 100

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

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

How many atoms in total are in 0,5 mol of water, H₂O?

1. A6,02 × 10²³
2. B9,03 × 10²³
3. C1,81 × 10²⁴
4. D3,01 × 10²³

Making ammonia (N₂ + 3H₂ ⇌ 2NH₃) is exothermic. A low temperature would give a higher yield, yet factories use a moderately high temperature. Why?

1. AAt low temperatures the reaction is too slow to be useful
2. BThe catalyst only works when the reaction is endothermic
3. CHigher temperatures shift the equilibrium toward more ammonia
4. DLow temperatures would make the ammonia explode