Chemistry for nursing entrance exams worksheet with answers

What is the half-life of a radioactive isotope?

1. AThe time taken for the mass of a sample to double in size
2. BThe time taken for half of the radioactive atoms in a sample to decay
3. CHalf the time it takes for all the atoms to decay
4. DHalf the number of protons in the nucleus

What is an exothermic reaction?

1. AA reaction that needs light to start
2. BA reaction in which no energy changes at all
3. CA reaction that releases heat to the surroundings
4. DA reaction that absorbs heat from the surroundings

What is the SI unit of energy?

1. AWatt
2. BJoule
3. CKelvin
4. DNewton

What is 380 mmHg in atmospheres?

1. A0.5 atm
2. B380 atm
3. C0.38 atm
4. D2 atm

How does a catalyst speed up a reaction?

1. AIt adds extra reactant to the mixture
2. BIt raises the temperature of the reactants so they move faster
3. CIt makes the reaction more exothermic
4. DIt provides a different pathway with a lower activation energy

Why do group 1 metals such as sodium react so easily?

1. AThey have a full outer shell of electrons
2. BTheir nuclei contain no neutrons
3. CThey easily gain one extra electron
4. DThey have one outer electron that is easily lost

For N₂ + 3H₂ → 2NH₃, 1 mol of N₂ is mixed with 2 mol of H₂. Which reactant is limiting?

1. AH₂, because 1 mol of N₂ would need 3 mol of H₂
2. BN₂, because there is less of it
3. CNeither, because both are used up exactly
4. DNH₃, because it is the product

Cells oxidise glucose to CO₂ and water, as burning glucose does. How does cellular respiration differ from burning?

1. AIt releases much more total energy than burning the same glucose
2. BIt releases the energy in many small, enzyme-controlled steps
3. CIt does not need oxygen at any stage
4. DIt produces different products from burning