A mixture of Cu2 and CuO of mass 8.828g is reduced to copper metal with hydrogen:
Cu2O + H2 --> 2Cu + H2O
CuO + H2 --> Cu + H2O
If the mass of pure copper isolated was 7.214g, determine the percent by mass of CuO in the original sample
Let x = grams of CuO in the original sample.
y = grams of Cu2O in the original sample.
Eq. #1 x + y = 8.828 grams
Molar mass of CuO = 63.5 + 16 = 79.5 grams
Moles of CuO = x ÷ 79.5
Molar mass of Cu2O = 63.546 + 32 = 95.5 grams
Moles of Cu2O = y ÷ 95.5
According to the 2nd balanced equation, CuO + H2 --> Cu + H2O ,
1 mole of CuO produces 1 mole of Cu.
So, x ÷ 79.5 moles of CuO will produce x ÷ 79.5 moles of Cu
According to the 1st balanced equation, Cu2O + H2 --> 2Cu + H2O,
1 mole of Cu2O produces 2 moles of Cu
So, (y ÷ 95.5) moles of Cu2O will produce 2 * (y ÷ 95.5) moles of Cu
Since, the mass of pure copper isolated was 7.214 grams
Moles of Cu = (7.214 ÷ 63.5)
Moles of Cu from Cu2O + moles of Cu from CuO = total moles of Cu!!
2 * (y ÷ 95.5) + (x ÷ 79.5) = (7.214 ÷ 63.5)
Multiply by both sides by 95.5 * 79.5 * 63.5 to get rid of denominators
(2 * 79.5 * 63.5) y + (95.5 * 63.5) x = (7.214 * 95.5 * 79.5)
10,096.5 y + 6,064.25 x = 36,418.0755
Divide both sides by 6,064.25
x + 1.665 y = 6
Eq.#2 x = 6 – 1.665 y
Eq. #1 x + y = 8.828
x = 8.828 – y
8.828 – y = 6 – 1.665 y
0.665 y = 2.828
y = 4.25 grams of Cu2O
x = 8.828 – 4.25 = 4.58 grams of CuO
% CuO = (4.58 ÷ 8.828) * 100 = 51.88% CuO
Answer:
To survive Global life expectancy is the highest it's ever been, with a global average lifespan of about 71.4 years as of 2015.
Explanation: took the test
<span>1. The correct option is A, THE OXYGEN ATOM HAS A NEGATIVE CHARGE. A water molecule is made up of two atoms of hydrogen and one atom of oxygen. The molecules of water are arranged in such a way that, the negative hydrogen atom is attracted to the positive hydrogen atom and the overall structure is bent. Because oxygen is more electronegative than hydrogen, oxygen atom draws the shared electrons toward itself , this gives the oxygen end of the molecule a partial negative charge and the hydrogen end, a partial positive charge.
2. The correct option is: WITHOUT THE PROPER BALANCE OF WATER, CHEMICAL REACTIONS WILL NOT TAKE PLACE. Metabolic chemical reactions take place in living cells all the time because water, which is a necessary condition for the reaction is in place. Th fluids find in the cells are mostly water; water creates suitable conditions for biochemical reactions to take place. Without water, the cells will not be able to carry out any chemical reaction.
3. The correct option is A. Hydrogen bond allows oxygen and water molecules to be bonded together. Hydrogen bonds are weak interactions that formed between the hydrogen with a patial positive end and oxygen with a patial negative end. The hydrogen bond in water is responsible for the unique properties associated with water.</span><span />
Answer:
A series circuit is defined as the circuit in which a number of resistances are connected one after the other.. In a series circuit, the flow of current follows a single path.
A parallel circuit is defined as the circuit in which a number of resistances are linked across each other in such a way that one terminal of each resistance is connected to form a junction point while the remaining end is also connected to form another point.
You havent added the diagram so i cant tell you the answer, but i added the definition of each circuit, see if that helps!
Answer:
Option A. It has stayed the same.
Explanation:
To answer the question given above, we assumed:
Initial volume (V₁) = V
Initial temperature (T₁) = T
Initial pressure (P₁) = P
From the question given above, the following data were:
Final volume (V₂) = 2V
Final temperature (T₂) = 2T
Final pressure (P₂) =?
The final pressure of the gas can be obtained as follow:
P₁V₁/T₁ = P₂V₂/T₂
PV/T = P₂ × 2V / 2T
Cross multiply
P₂ × 2V × T = PV × 2T
Divide both side by 2V × T
P₂ = PV × 2T / 2V × T
P₂ = P
Thus, the final pressure is the same as the initial pressure.
Option A gives the correct answer to the question.
