Answer:
The percent yield of this reaction is 70%
Explanation:
The reaction is: N₂ + 3H₂ → 2NH₃
We only have the mass of H₂, so we assume that N₂ is in excess
We convert the mass to moles, to work with the reaction:
450 g . 1mol / 2 g = 225 moles
Ratio is 2:3. 3 moles of H₂ can produce 2 moles of ammonia
Therefore 225 moles of H₂ will produce (225 .2)/ 3 = 150 moles
This is the 100% yield reaction → We convert the moles of NH₃ to mass
150 mol . 17g /1mol = 2550 g
Percent yield = (Produced yield/Theoretical yield) .100
Percent yield = (1575g/2550g) . 100 = 70%
Answer;
= 18.24
Explanation;
The ratio of N and O in the formula NO2 IS 1:2
Mass of nitrogen gas is 0.500 g
Moles of nitrogen will be;
= 0.500/16 = 0.03125 moles
Therefore;
The moles of Oxygen from the ratio will be;
= 0.03125 × 2 = 0.0625 moles
But; 0.0625 moles is equal to 1.140 g of Oxygen
The atomic number (mass in 1 mole) will be;
= 1.140 /0.0625
= 18.24
Thus the atomic number of Oxygen from the data is 18.24
Answer:

Explanation:
Hello!
In this case, since the chemical reaction between copper and nitric acid is:

By starting with 0.80 g of copper metal (molar mass = 63.54 g/mol) and considering the 1:1 mole ratio between copper and copper (II) nitrate (molar mass = 187.56 g/mol) we can compute that mass via stoichiometry as shown below:

However, the real reaction between copper and nitric acid releases nitrogen oxide, yet it does not modify the calculations since the 1:1 mole ratio is still there:

Best regards!
Here we have to calculate the heat required to raise the temperature of water from 85.0 ⁰F to 50.4 ⁰F.
10.857 kJ heat will be needed to raise the temperature from 50.4 ⁰F to 85.0 ⁰F
The amount of heat required to raise the temperature can be obtained from the equation H = m×s×(t₂-t₁).
Where H = Heat, s =specific gravity = 4.184 J/g.⁰C, m = mass = 135.0 g, t₁ (initial temperature) = 50.4 ⁰F or 10.222 ⁰C and t₂ (final temperature) = 85.0⁰F or 29.444 ⁰C.
On plugging the values we get:
H = 135.0 g × 4.184 J/g.⁰C×(29.444 - 10.222) ⁰C
Or, H = 10857.354 J or 10.857 kJ.
Thus 10857.354 J or 10.857 kJ heat will be needed to raise the temperature.