A sample of hydrogen gas occupies a volume of 4.1 Liters
at 105 kPa of pressure. What pressure, in kPa, would the
gas exert if the volume was decreased to 2.5 Liters?

p2=172.2KPA

Explanation:

use Boyle's law

p1 x v1 = p2 x v2

p1= 105 kpa

v1=4.1L

p2= ?

v2= 2.5L

substitute;

105 x 4.1 = p2 x 2.5

p2= ( 105 x 4.1)\2.5

p2=172.2KPA

petroleum? coal maybe?

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.