The answer to your question is: true.
Hope this helps!
To determine the number of moles(n) of a substance, divide its amount given in grams by the molar mass. The element in the problem is gold (Au) which has a molar mass of 196.97 grams per mole. The division is better illustrated below
n = 35.12 g / 196.97 grams per mole
The answer to the operation above is 0.1783 moles. Therefore, there are approximately 0.1783 moles of Au in 35.12 grams.
The answer is either A or C. Sorry I'm not much help :)
Answer:
Molar mass = 32.64 g / mol.
The density of gas is 1.3 × 10⁻³g/mL.
Explanation:
Given data:
Mass of sample = 2.35 g
Pressure = 1.05 atm
Volume = 1.85 L (1.85 × 1000 = 1850 ml)
Temperature = 55 °C (55+ 273.15 = 328.15 K)
Density = ?
Formula:
d = m/ v
The volume of flask would be the volume of gas.
d = 2.35 g / 1850 mL = 0.0013 g/mL or 1.3 × 10⁻³g/mL
The density of gas is 1.3 × 10⁻³g/mL.
Molar mass:
Now we will calculate the moles of a gas first in order to find the molar mass of a gas.
Formula:
PV =nRT
n = number of moles.
n = PV / RT
n = 1.05 atm × 1.85 L / 0.0821 atm. dm³. K⁻¹ . mol⁻¹ × 328.15 K
n = 1.9425 atm . L / 26.941115 atm . dm.³mol⁻¹
n = 0.072 mol
Now we will find the molar mass.
Number of moles = mass / molar mass
0.072 mol = 2.35 g / molar mass
Molar mass = 2.35 g / 0.072 mol
Molar mass = 32.64 g / mol
Answer:
The correct answer is Magnesium (Mg)
