When 3000 grams of water is cooled from 80.0 c to 10.0 c, how much energy is released

877800 Joules of energy is released

Explanation:

mass m = 3000 g

initial temperature = 80 c

Final temperature = 10 c

Change in temperature ΔT = 80 - 10 = 70 c

Heat H = ?

The relationship between these parameters is given by;

H = mcΔT

Where c = specific heat capacity = 4.18 J/gc

H = 3000 * 4.18 * 70 = 877800 Joules

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2