Answer:
a. [Na₂CrO₄] = 0.10 M
b. 0.017 moles of KBr
Explanation:
Molarity means a sort of concentration which indicates the moles of solute over 1L of solution.
We determine the moles of solute: 12.5 g / 162g/mol = 0.0771 moles
We convert the volume of solution from mL to L = 750 mL . 1L/1000mL = 0.750L
Molarity (mol/L) → 0.0771 mol / 0.750L = 0.10 M
b. In order to determine the moles of solute, with the molarity of solution and the volume we assume:
Molarity = moles of solute /volume of solution
Then, Molarity . Volume of solution (L) = moles of solute
We convert the volume of solution from mL to L = 150 mL . 1L/1000mL = 0.150L
0.112 mol/L . 0.150L = Moles of solute → 0.017 moles of KBr
Answer:
The answer is "17200 years".
Explanation:
Given:
Let the half-life of carbon-14, is beta emitter, is 
Constant decay 
The artifact age 
6 protons, 7 neutrons, and if it has no charge then it has 6 electrons
<span>C6H12 = 6x12 + 6x1 = 78.
The equation indicates that 2x78 = 156g benzene will produce 6542kJ.
Using proportions you can then calculate that
x/6542kJ = 7.9g / 156g
x = 331.3kJ = 331300J.
heat = mass x ΔT x 4.18J/g°
ΔT = 331300J / (5691g x 4.18J/g°) = 13.9°
final temp = 21 + 14° = 35°C</span>
Answer is b..............…
