Scheda di esercizi di Chimica per i test di ammissione a infermieristica con soluzioni

According to collision theory, what must happen for particles to react?

1. AThey must both be in the solid state at the same time
2. BThey must collide with enough energy and the right orientation
3. CThey must stay completely still next to each other
4. DThey must have the same mass

Which of these is a polyatomic ion?

1. ASulfate, SO₄²⁻
2. BChloride, Cl⁻
3. COxide, O²⁻
4. DSodium, Na⁺

What is an alloy?

1. AA nonmetal that conducts electricity
2. BA mixture of a metal with one or more other elements
3. CA pure metal in its natural state
4. DA compound formed when a metal reacts with oxygen

How does ionisation energy (the energy needed to remove an outer electron) generally change from left to right across a period?

1. AIt decreases
2. BIt stays the same
3. CIt first falls, then rises sharply
4. DIt increases

Sulfur has 16 electrons. In which period of the periodic table is it?

1. APeriod 16
2. BPeriod 6
3. CPeriod 3
4. DPeriod 2

How many lone (non-bonding) pairs of electrons are on the oxygen atom in a water molecule?

1. A4
2. B0
3. C1
4. D2

A mixture contains sand, salt and water. Which sequence separates all three?

1. AUse a magnet to remove the salt, then filter the sand
2. BDistil first to remove the sand, then filter out the salt
3. CEvaporate all the water first, then filter the salt away from the dry sand
4. DFilter to remove the sand, then distil the filtrate to collect water and leave salt

Why does a sodium ion (Na⁺) have almost the same mass as a sodium atom?

1. AIons and atoms always have exactly the same mass
2. BThe only difference is one electron, which has a tiny mass
3. CThe ion gains a neutron that balances the loss
4. DThe ion has one fewer proton, which has a tiny mass