Answer:
Number of moles of hydrogen are 0.022 mol.
Explanation:
Given data:
Volume of hydrogen = 546 mL
Temperature = 30°C
Pressure = 100.45 kpa
Number of moles of hydrogen = ?
Solution:
According to ideal gas equation,
PV = nRT
P = pressure
V = volume
n = number of moles
R = ideal gas constant
T = temperature
First of all we will convert the units,
Temperature = 30 + 273 = 303 K
Pressure = 100.45 /101 = 0.99 atm
Volume of hydrogen = 546 mL× 1L /1000 mL =0.546 L
Now we will put the values in formula,
PV = nRT
n = PV/RT
n = 0.99 atm × 0.546 L /0.0821 atm.L/mol.K × 303 K
n = 0.541 atm. L / 24.876 atm.L / mol
n = 0.022 mol
Answer:
%Cu = 66.4%
%S = 33.6%
Explanation:
Step 1: Given data
Step 2: Calculate the mass of S
The mass of CuS is equal to the sum of the masses of Cu and S.
mCuS = mCu + mS
mS = mCuS - mCu
mS = 9.56 g - 6.35 g = 3.21 g
Step 3: Calculate the percent by mass of each element
We will use the following expression.
%Element = mElement / mCompound × 100%
%Cu = mCu / mCuS × 100% = 6.35 g / 9.56 g × 100% = 66.4%
%S = mS / mCuS × 100% = 3.21 g / 9.56 g × 100% = 33.6%