Answer:
d = 1.8 × 10⁻⁴ kg/L
Explanation:
Given data:
Moles of helium = 2 mol
Temperature and pressure = standard
Density = ?
Solution:
PV = nRT
V = nRT/ P
V = 2 mol × 0.0821 atm. L/ mol. K × 273 K / 1 atm
V = 44.8 L
Mass of helium:
Mass = number of moles × molar mass
Mass = 2 mol × 4 g/mol
Mass = 8 g
Mass = 0.008 kg
Density;
Density = mass/ volume
d = 0.008 kg/ 44.8 L
d = 1.8 × 10⁻⁴ kg/L
Hey there!:
Molar mass CO2 = 44.01 g/mol
44.01 g CO2 ------------------- 6.02*10²² molecules CO2
88 g CO2 ------------------------ y
y = 88 * ( 6.02*10²² ) / 44.01
y = 5.29*10²⁵ / 44.01
y = 1.2 * 10²⁴ molecules of CO2
Answer A
Hope that helps!
Hey there!
NaHCO₃
Notice that there is no subscript under Na.
That means there is one atom of Na for each molecule of NaHCO₃.
Hope this helps!
The concentration of the solution is 4.25 M
Explanation
molarity=moles/volume in liters
moles = mass/molar mass
molar mass of HF = 19 + 1 = 20 g/mol
moles is therefore = 17.0 g/ 20 g/mol = 0.85 moles
volume in liters = 2 x10^2ml/1000 = 0.2 liters
therefore molarity = 0.85/0.2 = 4.25 M
3
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