Answer:
2 moles of Sn are produced when 4 moles of H2(g) are consumed completely
Explanation:
to determine the number of moles of sn (l) produced when 4.0 moles of H2 (g) is consumed completely.
First, find the number of moles of H2 consumed by taking this as limiting reagent.

Then find the moles of Sn (l) taking into account the stoichiometric relationship between H2(g) and Sn(l). 2:1
(s) + 2
(g) ⇒ Sn(l) + 2
(g)

∴2 moles of Sn are produced when 4 moles of H2(g) are consumed completely.
The list of options to answer this question is:
A.kinectic energy is transformed into thermal energy.
B.electrical energy is transformed into potential energy.
C.potential energy is transformed into kinectic energy.
D.mechanical energy is transformed into chemical energy.
The answer is the option A. A.kinectic energy is transformed into thermal energy.
As you know energy cannot be lost but transformed.
When friction force acts over the tyres it increases the speed of the particles in the tyres which is thermal energy, this thermal energy increase comes from kinetic energy loss.
Mass percentage of a solution is the amount of solute present in 100 g of the solution.
Given data:
Mass of solute H2SO4 = 571.3 g
Volume of the solution = 1 lit = 1000 ml
Density of solution = 1.329 g/cm3 = 1.329 g/ml
Calculations:
Mass of the given volume of solution = 1.329 g * 1000 ml/1 ml = 1329 g
Therefore we have:
571.3 g of H2SO4 in 1329 g of the solution
Hence, the amount of H2SO4 in 100 g of solution= 571.3 *100/1329 = 42.987
Mass percentage of H2SO4 (%w/w) is 42.99 %