Anonymous asked in Science & MathematicsChemistry · 8 years ago

Some Chemistry Higher/A-level questions!?

Hello there!

I'm currently sitting Higher Chemistry and done pretty bad on my first unit - I'm running through some question sheets I found and trying to work out the answers but I have no chance in class for my teacher to explain! If anyone could please explain how to do the following questions, I'd much appreciate it!

Which of the following chlorides is most likely to have the most ionic character?

A) LiCl B)CsCl C) BeCl2 D) CaCl2

2) Which of the following chlorides is most likely to be soluable in tetrachloromethane, CCl4?

a) Barium chloride b) caesium chloride c) calcium chloride d) phosphorous chloride

3) The avogadros constant is the same number of -

a) atoms in 24g of carbon

b) molecules in 16g of oxygen

c) molecules in 2g of hydrogen

d) ions in 1 litre of sodium chloride solution, concentration 1 mol

and in a similar vain to last question! -

4) The number of mols of ions in 1 mol of copper (II) phosphate is

A- 1 B - 2 C - 4 D - 5

Thank you:)

2 Answers

  • DavidB
    Lv 7
    8 years ago
    Favorite Answer

    1) look at the electronegativities of the two elements in each compound. The largest difference in elelctronegativity corresponds to the most ionic character.

    2) solublity rule: like dissolves like. CCl4 is a non polar solvent so will dissolve non polar solutes. d) is non-polar the rest are ionic

    3) avogadro's number is the number of particles in a mole of something (atoms or molecules or ions). The molar mass is the mass of a mole of something. So answer c); a) is 2 mol, b) is 0.5 mol, d) is 2 mol

    4) write the formula for the compound Cu3(PO4)2 so one mol has 5 mol of ions.

  • 4 years ago

    For nearly all elements on the identical row, the detail farther to the proper could have the bigger ionization energy. This is since there are more protons in the nucleus, pulling within the electrons with a bigger drive. As a result, it takes extra power to take away an electron if it has extra protons. Factors in staff thirteen vs. Team 2 (like Aluminum vs. Magnesium) are an exception, nevertheless. That is because factors in group 13 have 1 electron in a p orbital, and a couple of electrons in an s orbital. Elements in group 2 most effective have 2 electrons in an s orbital. It takes less energy to dispose of that one electron and create an empty p orbital than to interrupt apart an s orbital. They most of the time don't discuss this in high tuition chemistry, but s orbitals replenish first for the reason that they're more energetically favorable; for that reason this vigour change is more than enough to beat any extra energy it'll take considering that Aluminum has one more proton.

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