What causes the flame colors and the spectra?

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

What is the ima of the 1 st class lever in the graphic given? 2 3 0.5

For each of the following compounds, write the formula then predict whether it would be a strong, weak, or non-electrolyte when placed in di water. for the ionic compounds only, put (s) or (aq) after the forrmula formula strong, weak or non electrolyte? a calcium hydroxide b. silver carbonate c. lead(ii) sulfate d. phosphorus trifluoride e. sodium phosphide f barium sulfate g. strontium acetate h. zinc nitrate