Silicon can be made by heating a mixture of sand (silicon dioxide) with magnesium powder.
The equation for this reaction is shown below.
SiO2 (s)+ 2Mg (s) → 2MgO (s) + Si (s)
Calculate the mass of silicon dioxide needed to make 1 g of silicon.
Relative atomic masses: O = 16; Si = 28
Mass = ?

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚c inside a freezer for a night.  when he took it out, its new volume was 322 milliliters, but its pressure was the same.  if the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer? the temperature of the freezer is  kelvins.

Ibeg i need 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?

What is the relation between concentration of reactants and the rate of chemical reaction?