Molar mass is the given substance divided by the amount of that substance, measured in g/mol.
Example: titanium atomic mass is 47.88 amu or 47.88 g/mol. In 47.88 grams of titanium there is 1 mole, or 6.022 x 10^23 titanium atoms.
The mass of He gas = 21.428 g
<h3>Further explanation</h3>
Given
120 liters of He gas
Required
the mass in grams
Solution
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
Mol for 120 L :
Mass of He gas(MW=4 g/mol) :
Answer:
The answer to your question is 160 g of Calcium
Explanation:
Data
mass of Calcium = ?
mass of Hydrogen = 8 g
reactant = HCl
Process
1.- Write the balanced chemical reaction
Ca + 2HCl ⇒ CaCl₂ + H₂
2.- Look for the atomic number of Calcium and hydrogen
Calcium = 40 g
Hydrogen = 1 x 2 = 2 g
3.- Use proportions to calculate the mass of calcium needed.
40 g of Calcium ---------------- 2 g of hydrogen
x ----------------- 8 g of hydrogen
x = (8 x 40) / 2
x = 320/2
x = 160 g of Calcium
<span>Answer:
3 electron pairs
Let's take BF3 for an example.
When you find the valence electrons for this molecule --> [3+(3x6)], you'll get 24e-. You draw the Lewis dot structure and each of the F atom would have six dots around it (a total of 18 because there's 3 F atoms) and the B would have three lines [one line attached to each F. One line would equal to 2 valence electrons] and you get a total of 24 valence e-.
The question asks how many groups are on the CENTRAL atom, meaning on the B. It would be three</span>
