Energy is just like any other chemical or physical process, where it cannot be created or destroyed. Which Law states this fact?
1 answer:
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<u>Answer:</u> The mass of copper produced is 7.12 grams
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
.....(1)
Given mass of copper (I) sulfide = 8.80 g
Molar mass of copper (I) sulfide = 156.2 g/mol
Putting values in equation 1, we get:
The chemical equation for the reaction of copper (I) sulfide and oxygen gas follows:
By Stoichiometry of the reaction:
1 mole of copper (I) sulfide produces 2 moles of copper
So, 0.056 moles of copper (I) sulfide will produce = of copper
Now, calculating the mass of copper from equation 1, we get:
Molar mass of copper = 63.55 g/mol
Moles of copper = 0.112 moles
Putting values in equation 1, we get:
Hence, the mass of copper produced is 7.12 grams
Answer:
0.51M
Explanation:
Given parameters:
Initial volume of NaBr = 340mL
Initial molarity = 1.5M
Final volume = 1000mL
Unknown:
Final molarity = ?
Solution;
This is a dilution problem whereas the concentration of a compound changes from one to another.
In this kind of problem, we must establish that the number of moles still remains the same.
number of moles initially before diluting = number of moles after dilution
Number of moles = Molarity x volume
Let us find the number of moles;
Number of moles = initial volume x initial molarity
Convert mL to dm³;
1000mL = 1dm³
340mL gives = 0.34dm³
Number of moles = initial volume x initial molarity = 0.34 x 1.5 = 0.51moles
Now to find the new molarity/concentration;
Final molarity = =
= 0.51M
We can see a massive drop in molarity this is due to dilution of the initial concentration.