The energy transfers occurring in a car engine change chemical energy into . i. kinetic energy ii. sound energy iii. heat energy
a. only i
b. i, ii, and iii
c. i and ii
d. i and iii

C. I and II

Explanation:

The energy conversion in a car engine is quite interesting.

It starts with chemical energy which is obtained by burning of gasoline in the engine. Burning gasoline releases a form of thermal energy which heat. The heat is converted into mechanical energy which causes the motion of the car by driving pistons. The chemical energy is a potential energy source.

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g