1.
V = 200 mL (volume)
c = 3 M = 3 mol/L (concentration)
First we convert mL to L:
200 mL = 0.2 L
Then we calculate the moles using the formula: n = V × c = 0.2 L × 3 mol = 0.6 mol
Finally, we just use the molar mass of CaF2 to calculate the actual mass:
molar mass = 78 g/mol
The formula is: m = n × mm (mass = moles × molar mass)
m = 0.6 mol × 78 g/mol = 46.8 g
2.
For this question the steps are exactly like the first question.
V = 50mL = 0.05 L
c = 12 M = 12 mol/L
n = V × c = 0.05 L × 12 mol/L = 0.6 mol
molar mass (HCl) = 36.5 g/mol
m = n × mm = 0.6 mol × 36.5 g/mol = 21.9 g.
3.
The steps for this question are the opposite way.
m(K2CO3) = 250 g
molar mass = 138 g/mol
n = m ÷ mm = 1.81 mol
c = 2 mol/L
V = n ÷ c = 1.81 mol ÷ 2 mol/L = 0.905 L = 905 mL
Look on this website!
http://lawr.ucdavis.edu/classes/ssc100/CEC_Answers02.htm
Answer:
AgNO2
Explanation:
The question asks to know which of these two insoluble salts is expected to be more soluble in acidic solution than in pure water.
To answer this question specifically, we need to know if the anions contained in the insoluble salt is a conjugate of a weak acid or that of a weak base.
Generally, the solubility of insoluble salts that contain anions which are conjugates of weak acids increases in the presence of an acidic solution than in water. While, the solubility of insoluble salts that contain anions which are conjugates of strong acids decreases in the presence of an acidic solution.
Having said this, AgNO2 contains NO2 which is the conjugate base of the Trioxonitrate iii acid which is a weak acid. Hence, it is expected to be stronger in acidic solution than in water.
Answer:
394.76g
Explanation:
Given parameters:
Mass of Phosphorus = 172.1g
Unknown:
Mass of P₂O₅ = ?
Solution:
We should work from the known specie to the unknown in this problem. The limiting reactant is the reactant in short supply and it determines the extent of the reaction. This is the given phosphorus.
Oxygen is in the excess.
The balanced reaction equation:
4P + 5O₂ → 2P₂O₅
let us find the number of moles of phosphorus first,
Number of moles of phosphorus = 
Molar mass of phosphorus = 31g/mole
Number of moles = 
= 5.55mole
4 moles of phosphorus gives 2 moles of P₂O₅
5.55 mole of P will produce 
= 2.78moles
Mass of P₂O₅ = number of moles x molar mass
Molar mass of P₂O₅ = (31 x 2) + (16 x 5) = 142g/mole
Mass of P₂O₅ = 2.78moles x 142g/mole = 394.76g
