Given parameters:
Volume of CuSO₄ = 250mL
Concentration of CuSO₄ = 2.01M
Unknown:
Mass of CuSO₄.5H₂O = ?
To solve this problem, we must write the chemical relationship between both species.;
CuSO₄.5H₂O → CuSO₄ + 5H₂O
Now that we know the expression, it is possible to solve for the unknown mass.
First find the number of moles of CuSO₄;
Number of moles = Concentration x Volume
Take 250mL to L so as to ensure uniformity of units;
Volume = 250 x 10⁻³L
Input the parameters and solve for number of moles;
Number of moles = 250 x 10⁻³ x 2.01 = 0.5mol
From the equation;
1 mole of CuSO₄ is produced from 1 mole of CuSO₄.5H₂O
So 0.5 moles of CuSO₄ will be produced from 0.5 moles of CuSO₄.5H₂O
Now let us find the molar mass of CuSO₄.5H₂O = 63.6 + 32 + 4(16) + 5(2x1 + 16) = 249.6g/mole
Mass of CuSO₄.5H₂O = number of moles x molar mass
= 0.5 x 249.6
= 124.8g
The mass of CuSO₄.5H₂O is 124.8g
It is an endothermic reaction because the products hAve more heat than the reactions so it was a gain of heat which makes the enthalpy Change positive !
Answer:
Mass = 15.20 g of KCl
Explanation:
The balance chemical equation for the decomposition of KClO₃ is as follow;
2 KClO₃ = 2 KCl + 3 O₂
Step 1: Calculate moles of KClO₃ as;
Moles = Mass / M/Mass
Moles = 25.0 g / 122.55 g/mol
Moles = 0.204 moles
Step 2: Find moles of KCl as;
According to equation,
2 moles of KClO₃ produces = 2 moles of KCl
So,
0.204 moles of KClO₃ will produce = X moles of KCl
Solving for X,
X = 2 mol × 0.204 mol / 2 mol
X = 0.204 mol of KCl
Step 3: Calculate mass of KCl as,
Mass = Moles × M.Mass
Mass = 0.204 mol × 74.55 g/mol
Mass = 15.20 g of KCl
Answer:
B - The energy of reactants is conserved.
D - the nuclei of atoms changes completely ( if that's the option)
