Užduočių lapas tema Chemija slaugos stojamiesiems egzaminams su atsakymais

What does organic chemistry study?

1. ACompounds made of metals
2. BOnly compounds found in plants
3. CCompounds based on carbon
4. DOnly the noble gases

What does the rule "like dissolves like" mean?

1. AEvery substance dissolves in water
2. BSolids dissolve only in other solids
3. CPolar solvents dissolve polar substances, and nonpolar solvents dissolve nonpolar ones
4. DOnly substances with identical formulas can ever dissolve in each other

What is a beta particle?

1. AA wave of visible light
2. BA helium nucleus with two protons and two neutrons
3. CA neutron that leaves the nucleus
4. DA high-energy electron released from a nucleus

Why does ice float on liquid water?

1. AIce is less dense than liquid water
2. BIce is denser than liquid water
3. CIce contains trapped air from the freezer
4. DIce has a higher mass than the same volume of water

How does a catalyst speed up a reaction?

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

When a nucleus emits an alpha particle, how do its mass number and atomic number change?

1. ANeither changes
2. BMass number falls by 2 and atomic number falls by 4
3. CMass number falls by 4 and atomic number falls by 2
4. DMass number stays the same and atomic number rises by 1

Why is it easier to remove the outer electron from a potassium atom than from a lithium atom?

1. APotassium's outer electron is in a full shell
2. BPotassium has fewer protons, so its nucleus pulls much more weakly on every electron
3. CPotassium's outer electron is farther from the nucleus and more shielded by inner electrons
4. DLithium has more electron shells than potassium

Magnesium burns as 2Mg + O₂ → 2MgO. What mass of MgO (40 g/mol) forms from 48 g of Mg (24 g/mol)?

1. A40 g
2. B80 g
3. C48 g
4. D160 g