Use the Heat formula for both problems.
q=m*c*∆t
Where
q= heat in Joules
m= mass in grams
c= specific heat which is a constant 4.18
∆t= change in temperature
Answer:
513.74 g of solution
Explanation:
% Mass grams are defined as the <em>grams that are dissolved in salt</em> (in this case, it would be <em>potassium nitrate</em>) <em>dissolved every 100 g of the solution</em>. Having this information, you can calculate the amount of solution that has dissolved 18.7 g of potassium nitrate, which is what we want to obtain.
The relationship is:
3.64 g of potassium nitrate _____ 100 g solution
18.7 g of potassium nitrate _____ X = 513.74 g of solution
Calculation: 18.7g x 100g / 3.64g = 513.74 g of solution
So, <em>I need 513.74 g of solution to get 18.7g of potassium nitrate by evaporating it</em>.
<u>Given:</u>
Moles of Al = 0.4
Moles of O2 = 0.4
<u>To determine:</u>
Moles of Al2O3 produced
<u>Explanation:</u>
4Al + 3O2 → 2Al2O3
Based on the reaction stoichiometry:
4 moles of Al produces 2 moles of Al2O3
Therefore, 0.4 moles of Al will produce:
0.4 moles Al * 2 moles Al2O3/4 moles Al = 0.2 moles Al2O3
Similarly;
3 moles O2 produces 2 moles Al2O3
0.4 moles of O2 will yield: 0.4 *2/3 = 0.267 moles
Thus Al will be the limiting reactant.
Ans: Maximum moles of Al2O3 = 0.2 moles
Answer:
7
Explanation:
Given that the total charge is given by;
C =nq
Where;
n = number of charges
q = quantity of charge
Where the total amount of charge is -1.12 x 10-18 C and the magnitude of each charge is -1.602 x 10-19 C
Then the number of electrons is obtained from;
n = -1.12 x 10-18 C/ -1.602 x 10-19 C
n = 7
