M = m/L
moles of CaO = 2.75g / molar mass
2.75g/ 56.08g = 0.049moles CaO
155mL / 1000 = 0.155 L
M= 0.049moles/0.155L
M=0.316
Answer:
2.35 L
Explanation:
Given data:
Mass of sodium metal = 4.81 g
Volume of Cl react at STP= ?
Balance chemical equation = ?
Solution:
Balance chemical equation:
2Na + Cl₂ → 2NaCl
Number of moles of Na:
Number of moles = mass/ molar mass
Number of moles = 4.81 g/ 23 g/mol
Number of moles = 0.21 mol
Now we will compare the moles of sodium and chlorine from balance chemical equation.
Na : Cl₂
2 : 1
0.21 : 1/2×0.21 = 0.105 mol
Volume of Cl₂:
PV = nRT
standard temperature = 273 K
standard pressure = 1 atm
R = general gas constant = 0.0821 atm.L/mol.K
n = moles = 0.105 mol
Now we will put the values.
V = 0.105 mol × 0.0821 atm.L/mol.K × 273 K / 1 atm
V = 2.35 L/ 1
V = 2.35 L
?..................................
If the question does not require unit conversion (mL to L) then:
density = mass / volume
density . volume = mass
19.3g/mL . 50 mL =mass
965 g= mass
