PLEASE HELP ME!!:((( When hydrogen chloride reacts with magnesium, magnesium chloride and hydrogen gas are formed.

If 10.1 g of magnesium react with 26.0 g of hydrogen chloride,
1-what is the limiting reagent?
2- Theoretically how much hydrogen gas can be formed?
3- How much of the excess reagent is left over after the reaction is complete?
4- If 0.35 grams of hydrogen gas are actually formed and recovered in the reaction, what is the percent yield??

What type of reaction is shown below? check all that apply. 2h2o2 → 2h2o + o2 synthesis decomposition combustion

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Equal numbers of moles of he(g), ar(g), and ne(g) are placed in a glass vessel at room temperature. if the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?