The specific heat of wood is 2.03 (J/gºC). How much heat is needed to convert 550
grams of wood at 15°C down to 10 °C?

-5582.5J

Explanation:

The quantity of Heat Energy (Q) required to heat a substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)

Thus, Q = MCΦ

Since,

Q = ?

Mass of wood = 550 grams

C = 2.03 (J/gºC)

Φ = (Final temperature - Initial temperature)

= 10°C - 15°C = -5°C

Then, Q = MCΦ

Q = 550g x 2.03J/gºC x -5°C

Q = -5582.5J

Thus, -5582.5 joules of heat is needed convert 550 grams of wood at 15°C down to 10 °C

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