The copper has a normal atomic mass of 63.546

it's atomic number is 29

it's atomic mass is 63 disregarding other mass in atom
Atomic mass - atomic number = neutron mass

63 - 29 = 34

Hope this helps

6 0

4 years ago

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A sample of gas occupies a volume of 50.0 milliliters in a cylinder with a movable piston. The pressure of the sample is 0.90 at

alina1380 [7]

P₁ = 0.90 atm

V₁ = 50.0 mL

T₁ = 298 K

P₂ = 1 atm

T₂ = 273 K

V₂ = P₁ x V₁ x T₂ / T₁ x P₂

V₂ = 0.90 x 50.0 x 273 / 298 x 1

V₂ = 12285 / 298

V₂ = 41 mL

Answer (1)

hope this helps!

7 0

3 years ago

Natural gas burns in air to form carbon dioxide and water, releasing heat. CH4(g)+2O2(g)→CO2(g)+2H2O(g) ΔHrxn = -802.3 kJ.

Olenka [21]

Answer:

1) Minimum mass of methane required to heat 45.0 g of water by 21.0°C is 0.0788 g.

2) Minimum mass of methane required to heat 50.0 g of water by 26.0°C is 0.108 g.

Explanation:

$CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g) ,\Delta H_{rxn} =-802.3 kJ$

1) Minimum mass of methane required to raise the temperature of water by 21.0°C.

Mass of water = m = 45.0 g

Specific heat capacity of water = c = 4.18 J/g°C

Change in temperature of water = ΔT = 21.0°C.

Heat required to raise the temperature of water by 21.0°C = Q

$Q=mc\Delta T= 45.0 g\times 4.18 J/g^oC\times 21.0^oC$

Q = 3,950.1 J = 3.9501 kJ

According to reaction 1 mole of methane on combustion gives 802.3 kJ of heat.

Then 3.950.1 kJ of heat will be given by:

$=\frac{3.950.1 kJ}{802.3 kJ}=0.004923 mol$

Mass of 0.004923 moles of methane :

0.004923 mol × 16 g/mol=0.0788 g

Minimum mass of methane required to heat 45.0 g of water by 21.0°C is 0.0788 g.

2) Minimum mass of methane required to raise the temperature of water by 26.0°C.

Mass of water = m = 50.0 g

Specific heat capacity of water = c = 4.18 J/g°C

Change in temperature of water = ΔT = 26.0°C.

Heat required to raise the temperature of water by 21.0°C = Q

$Q=mc\Delta T= 50.0 g\times 4.18 J/g^oC\times 26.0^oC$

Q = 5,434 J= 5.434 kJ

According to reaction 1 mole of methane on combustion gives 802.3 kJ of heat.

Then 5.434 kJ of heat will be given by:

$=\frac{5.434 kJ}{802.3 kJ}=0.006773 mol$

Mass of 0.006773 moles of methane :

0.006773 mol × 16 g/mol= 0.108 g

Minimum mass of methane required to heat 50.0 g of water by 26.0°C is 0.108 g.

6 0

4 years ago