Answer:
A) Is The Correct Answer
<em><u>PLEASE</u></em><em><u> </u></em><em><u>MARK</u></em><em><u> </u></em><em><u>AS</u></em><em><u> </u></em><em><u>BRAINLIEST</u></em><em><u> </u></em><em><u>ANSWER</u></em><em><u> </u></em>
Answer:
This question lacks options, the options are;
A. Absorption of heat
B. A chemical change
C. A physical change
D. Formation of a new compound
The answer is C. A physical change
Explanation:
A physical change is a type of change that does not involve the chemical composition of the substance(s) involved. Physical changes affect the form but not the chemical content of a substance. Examples of physical changes are freezing, change of state, boiling etc.
In this question, a liquid is cooled during an investigation causing it to solidify. The cooling of this liquid represents a PHYSICAL CHANGE because the liquid state of the substance is only changed to a solid state but does not involve changing the chemical composition of the substance.
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:
Measure the diameter of the circle using Ruler A and Ruler B.
Given that the actual diameter of the circle is 2.264 cm, classify the following statements that describe the diameter measurement of the circle according to the ruler.
Drag the appropriate items to their respective bins.
I think this is the answer you was looking for hope this helps !!!
