The specific heat of copper is 0.4 J/g^ *C If a sample of copper absorbs 480J of energy and its temperature changes from 20.0 ^* c to 60.0 ^ * C what mass of copper was heated?

The mass of copper that was heated is 30 g

Explanation:

The formula for the heat supplied, ΔH is;

ΔH = m·c·Δt

Where:

ΔH = Heat supplied = 480 J

m = Mass of the copper sample = Required

c = Specific heat capacity of copper = 0.4 J/(g·°C)

Δt = Change in temperature = T₂ - T₁ = 60° - 20° = 40°C

T₁ = Initial temperature = 20°C

T₂ = Final temperature = 60°C

Therefore, plugging the values, we have;

480 = m×0.4×40

m = 480/(0.4 × 40) = 30 g

The mass of copper that was heated = 30 g.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.