Balancing Equations?

10) Hydrofluoric acid is used to etch grooves in
glass because it reacts with the silica (SiO2(s))
in glass. The products of the reactions are
aqueous silicon tetrafluoride and water. What
is the coefficient of water in the balanced
equation for the reaction? (Balance the equa-
tion with the smallest possible whole number
coefficients.)

11) When H2 and O2 react, water vapor is pro-
duced. What type of reaction is this?

12) Which of the following series of metals is cor-
rectly ranked in order of increasing activity?
1. Au < Zn < Na < Li 2. Au < Zn < Li < Na 3. Na < Li < Zn < Au 4. Au < Na < Li < Zn 5. Li < Na < Zn < Au 13) What is the order of reactivity (from most to least) of A, B, C, H2 in the following processes. A + 2 HCl=H2 + ACl2 B + HCl=No Reaction C + HCl=No Reaction B + CCl2=2 BCl + C 1. C, A, H2, No Reaction 2. A, H2, B, C 3. C, B, H2, A 4. H2, C, A, B