Answer:
This question is incomplete, here's the complete question:
<em><u>"Suppose 0.0842g of potassium sulfate is dissolved in 50.mL of a 52.0mM aqueous solution of sodium chromate. Calculate the final molarity of potassium cation in the solution. You can assume the volume of the solution doesn't change when the potassium sulfate is dissolved in it. Round your answer to 2 significant digits."</u></em>
Explanation:
Reaction :-
K2SO4 + Na2CrO4 ------> K2CrO4 + Na2SO4
Mass of K2SO4 = 0.0842 g, Molar mass of K2SO4 = 174.26 g/mol
Number of moles of K2SO4 = 0.0842 g / 174.26 g/mol = 0.000483 mol
Concentration of Na2CrO4 = 52.0 mM = 52.0 * 10^-3 M = 0.052 mol/L
Volume of Na2CrO4 solution = 50.0 ml = 50 L / 1000 = 0.05 L
Number of moles of Na2CrO4 = 0.05 L * 0.052 mol/L = 0.0026 mol
Since number of moles of K2SO4 is smaller than number of moles Na2CrO4, so 0.000483 mol of K2SO4 will react with 0.000483 mol of Na2CrO4 will produce 0.000483 mol of K2CrO4.
0.000483 mol of K2CrO4 will dissociate into 2* 0.000483 mol of K^+
Final concentration of potassium cation
= (2*0.000483 mol) / 0.05 L = 0.02 mol/L = 0.02 M
The statue will weather faster because of more surface area.
The volume of 0.20 moles of helium at STP is 4.5 liters.
Explanation:
Given:
Number of moles = 0.20 moles
To Find:
The volume of Helium at STP =?
Solution:
According to ideal gas law
PV = nRT
where
P is pressure,
V is volume,
n is the number of moles
R is the gas constant, and
T is temperature in Kelvin.
The question already gives us the values for p and T
,because helium is at STP. This means that temperature is 273.15 K and pressure is 1 atm
.
We also already know the gas constant. In our case, we'll use the value of
0.08206 L atm/K mol since these units fit the units of our given values the best
On substituting these values we get



V = 4.5 Liters
Just dived both numbers by two