In the reaction mg (s) + 2hcl (aq) h2 (g) + mgcl2 (aq), how many moles of hydrogen gas will be produced from 75.0 milliliters of a 1.0 m hcl in an excess of mg?

Naoki's bicycle has a mass of 10 kg. if naoki sits on her bicycle and starts pedaling with a force of 168 n, causing an acceleration of 2.8 m/s2, what is naoki's mass?

Asolution contains 225 g of sodium chloride, nacl, dissolved in enough water to make a 0.25 l of solution. what is the molarity of the solution?

Can someone me with 3 and 4 plz. this is for masteries test.