Answer:
- 40.66
- 9.91
Explanation:
For the first question:
Our theoretical compound is MR₂
1 mol of MR₂ contains 1 mol of M and 2 moles of R
Let's find out the molar mass:
9.45 g/mol + 18.12 g/mol . 2 = 45.69 g/mol
We can solve this, by an easy rule of three:
1 mol of MR₂ weighs 45.69 grams
Then, 0.89 moles may weigh 40.66 g
For the second question:
Our theoretical compound is D₂G
Let's determine the molar mass:
11.45 g/mol . 2 + 44.57 g/mol = 67.47 g/mol
1 mol of anything contains 6.02×10²³ molecules. By this definition we can say that 6.02×10²³ molecules weigh 67.47 grams. Let's solve by the rule of three:
6.02×10²³ molecules weigh 67.47 g
8.84×10²² molecules may weigh (8.84×10²² . 67.47 ) / 6.02×10²³ = 9.91 g
0,51%, the moles of the ions are 0,025 moles and the concentration in moles/L are 0,005M
109/8.56=12.7
50+12.7
V=62.7
Mass= Volume x Density so i divided the mass and density to get the volume. and afterwards i would just add it to the mass to get my final answer
The brother is represented by variable b.
The sister is represented by the variable s.
This means:
b+s=26
Answer:
Mass of Ca(OH)₂ required = 0.09 g
Explanation:
Given data:
Volume of HNO₃ = 25 mL (25/1000 = 0.025 L)
Molarity of HNO₃ = 0.100 M
Mass of Ca(OH)₂ required = ?
Solution:
Chemical equation;
Ca(OH)₂ + 2HNO₃ → Ca(NO)₃ + 2H₂O
Number of moles of HNO₃:
Molarity = number of moles / volume in L
0.100 M = number of moles / 0.025 L
Number of moles = 0.100 M ×0.025 L
Number of moles = 0.0025 mol
Now we will compare the moles of Ca(OH)₂ with HNO₃ from balance chemical equation.
HNO₃ : Ca(OH)₂
2 : 1
0.0025 : 1/2×0.0025 = 0.00125
Mass of Ca(OH)₂:
Mass = number of moles × molar mass
Mass = 0.00125 mol × 74.1 g/mol
Mass = 0.09 g
