Using dimensional analysis, we can find the moles of strontium by comparing the mass of strontium to it's atomic mass.
You can find the atomic mass of Sr on the periodic table:
Atomic Mass Sr = 87.62g/mol
In case you are not familiar, dimensional analysis works like this:
(what we know) x (conversion factor) = what we are looking for
The conversion factor compares the units of what we know to the units of what we are looking for. In this case, the conversion factor is:
1 mol/87.62g
The important thing to note about the conversion factor is that you want to be able to cancel out the units of your given measurement (in this case, it is the mass)
So, our full solution will be:
moles Sr = (175.24 g)x(1 mol/87.62 g)
(cancel out the mass units)
moles Sr = 175.24 x 1 mol/87.62
= 2.00 mol Sr
Hope this helped you!
Answer:
Percent yield = 86.2%
Explanation:
Given data:
Mass of zinc = 3.68 g
Mass of zinc chloride = ?
Percent yield = ?
Actual yield = 7.12 g
Solution:
Chemical equation:
Zn + 2HCl → ZnCl₂ + H₂
Number of moles of zinc:
Number of moles = Mass /molar mass
Number of moles = 3.68 g / 65.38 g/mol
Number of moles = 0.06 mol
Now we will compare the moles of ZnCl₂ with zinc.
Zn : ZnCl₂
1 : 1
0.06 : 0.06
Theoretical yield of zinc chloride:
Mass of ZnCl₂ = moles × molar mass
Mass of ZnCl₂ = 0.06 mol × 136.286 g/mol
Mass of ZnCl₂ = 8.2 g
Percent yield:
Percent yield = actual yield / theoretical yield × 100
Percent yield = 7.12 g/ 8.2 g × 100
Percent yield = 86.2%
Answer:
It would be higher than expected.
Explanation:
Respiration quotient (RQ) may be defined as the quantity used for the representation of the basal metabolic rate. This mainly depends on the amount of the carbon dioxide.
The respiratory quotient represents the ratio of carbon dioxide eliminated with the amount of the oxygen consumed. During stress condition, the oxygen consumption of our body increase and more carbon dioxide is exhale out from the body. This will increase the RQ.
Thus, the answer is RQ will be higher than expected.
The relation between moles and mass is given by the formula:
# of moles = (mass in grams) / (molar mass)
So, given the molar mass of 18.02 and 0.025 mol, you can solve the formula for the mass of water in grams:
mass of water in grams = # of moles of water * molar mass of water
mass of water in grams = 0.025 mol * 18.02 g / mol = 0.4505 g of water.
Then, she is wrong.
