1 mole Hg --------------- 6.02x10²³ atoms
?? moles Hg ------------ 1.30x10⁷ atoms
(1.30x10⁷) x 1 / 6.02x10²³ => 2.159x10⁻¹⁷ moles
Answer:
Molar mass of solute is 89.28 g/m
Explanation:
Colligative property of freezing point depression to solve this:
ΔT = Kf . m . i
i = number of particles, dissolved in solution. In this case, it is a nonelectrolyte, so i = 1.
m = molalilty (mol of solute/1kg of solvent
ΔT = T° freeze pure solvent - T° freeze solution
0°C - (-2.50°C) = 1.86 °C/m . m
2.50°C / 1.86 m/°C = m
1.34 mol solute/kg solvent = m
This means, that in 1000 g of solvent, we have 1.34 moles but we have 250 g of solvent, so let's make a rule of three.
1000 g ____ 1.34 moles
250 g _____(2.50 . 1.34) / 1000 = 0.336 moles
To find the molar mass, we divide mass / moles
30 g/ 0.336 moles = 89.28 g/m
Answer:
Option D. 30 mL.
Explanation:
Step 1:
The balanced equation for the reaction. This is given below:
HNO3 + KOH —> KNO3 + H2O
From the balanced equation above,
The mole ratio of the acid, nA = 1
The mole ratio of the base, nB = 1
Step 2:
Data obtained from the question. This include the following:
Volume of base, KOH (Vb) =.?
Molarity of base, KOH (Mb) = 0.5M
Volume of acid, HNO3 (Va) = 10mL
Molarity of acid, HNO3 (Ma) = 1.5M
Step 3:
Determination of the volume of the base, KOH needed for the reaction. This can be obtained as follow:
MaVa / MbVb = nA/nB
1.5 x 10 / 0.5 x Vb = 1
Cross multiply
0.5 x Vb = 1.5 x 10
Divide both side by 0.5
Vb = (1.5 x 10) /0.5
Vb = 30mL
Therefore, the volume of the base, KOH needed for the reaction is 30mL.
Answer:
Prevent any European country from growing much stronger than its neighbors.
Explanation:
