Answer:
A) 900 J
B) 27.96 J
C) 1,628 J ≅ 1.63 kJ
Explanation:
The heat absorbed by the metal (silver) - or energy required to heat it - is calculated as:
heat = mass x Cp x ΔT
Where Cp is the heat capacity (0.24 J/°C ·g) and ΔT is the change in temperature (final T - initial T).
A) Given:
mass = 150.0 g
final T = 298 K = 25°C
initial T = 273 K = 0°C
We calculate the energy in J to raise the temperature:
heat = mass x Cp x (final T - initial T)
= 150 .0 g x 0.24 J/°C ·g x (25°C - 0°C )
= 900 J
B) Given:
moles Ag= 1.0 mol
ΔT = 1.08°C
We first calculate the mass of silver (Ag) by multiplying the moles of Ag by the molar mass of Ag (MM = 107.9 g/mol)
mass = moles x MM = 1.0 mol Ag x 107.9 g/mol Ag = 107.9 g
Then, we calculate the heat required:
heat = mass x Cp x ΔT = 107.9 g x 0.24 J/°C ·g x 1.08°C = 27.96 J
C) Given:
heat = 1.25 kJ = 1,250 J
final T = 15.28°C
initial T = 12.08°C
We first calculate the change in temperature:
ΔT = final T - initial T = 15.28°C - 12.08°C = 3.2°C
Then, we calculate the mass of silver:
mass = heat/(Cp x ΔT) = 1,250 J/(0.24 J/°C ·g x 3.2°C) = 1,628 J ≅ 1.63 kJ
Explanation:
Pure subsance is a substance that is made up of only one type of particle - each piece is the same throughout.
Being present before the reaction but not after means it's no the same (it couldve evaporated)
<span>
Mn²⁺ + 4H2O -----> MnO4⁻ + 8H⁺ +5e⁻ /*2
<span>NaBiO3 +6H⁺ +2e⁻ -----> Bi³⁺ + Na⁺ + 3H2O /*5
</span>2Mn²⁺ + 5 NaBiO3+8H2O+30H⁺ ---> 2MnO4⁻ +5Bi³⁺ + 5Na⁺ +16H⁺ +15H2O
</span>2Mn²⁺ + 5 NaBiO3+14H⁺ ---> 2MnO4⁻ +5Bi³⁺ + 5Na⁺ +7H2O
There are 7 water molecules in this reaction.
Explanation:
We have to find the number of moles of N₂ that are present in a sample that has a volume of 40.0 L at STP.
STP means Standard Conditions of Temperature and Pressure. These conditions are 273.15 K and 1 atm. We know that 1 mol of N₂ will occupy 22.4 L. We can use that ratio to find the answer to our problem.
1 mol of N₂ = 22.4 L
moles of N₂ = 40.0 L * 1 mol/(22.4 L)
moles of N₂ = 1.79 mol
Answer: 1.79 moles of nitrogen are present.
