Suppose it took 108 joules of energy to raise a bar of gold from 25 °C to 29.7°C. Given that the specific heat capacity of gold is 0.128 J/g °C, what is the mass (in grams) of the bar of gold?

m = 180 g

Explanation:

Given data:

Energy absorbed = 108 J

Mas of gold = ?

Initial temperature = 25°C

Final temperature = 29.7 °C

Specific heat capacity of gold = 0.128 J/g.°C

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT =29.7 °C - 25°C

ΔT = 4.7 °C

108 J = m ×0.128 J/g.°C ×4.7 °C

108 J = m ×0.60 J/g

m = 108 J/0.60 J/g

m = 180 g

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.