We are asked to calculate the number of moles in a given mass of a substance. To be able to calculate it, we need the molar mass of the substance. For (NH4)2Cr2O7, the molar mass would be <span>252.07 g/mol. We calculate as follows:
0.025 g </span>(NH4)2Cr2O7 ( 1 mol / 252.07 g ) = 0.0001 mol <span>(NH4)2Cr2O7
Hope this answers the question. Have a nice day.</span>
I will solve this question assuming the reaction equation look like this:
<span>MnO2 + 4 HCl ---> MnCl2 + Cl2 + 2 H2O.
</span>
For every one molecule of MnO2 used, there will be one molecule of Cl2 formed. If the molecular mass of MnO2 is 87g/mol and molecular mass of Cl2 is <span> 73.0 g/mol, the mass of MnO2 needed would be:
Cl mass/Cl molecular mass * MnO2 molecular mass=
25g/ (73g/mol) * (87g/mol) * 1/1= 29.8 grams</span>
Answer:
Explanation:
Hello,
In this case, considering that the by-mass percent of water is:
Given such percent and the mass of the sample, we can find the mass of water in grams in the sample by solving for it as shown below:
Best regards.
<span>1 ml of water weighs 1 gram so 1 liter (1000 ml) weighs 1000 grams. A 3% solution (3% = 0.03) of hydrogen peroxide (w/v) would contain 1000 grams x 0.03 or 30 grams. The chemical formula of hydrogen peroxide is H2O2 and a mole weighs 34.0147 grams/mole. So 30 grams of H2O2 divided by 34.0147 grams/mole equals 0.88 moles of H2O2. The concentration of a 3% (w/v) hydrogen peroxide solution therefore contains 30 grams of H202 (or 0.88 moles of H202) per in a liter of water (or 1000 grams H20) would thus be 0.88 moles H2O2 per liter (0.88 moles H2O2/l) .</span>
The mean is simply the arithmetic average of all your raw data. This can be solved methodically by summing up all of the raw data points that you have. Take note how many raw data points you used, because this will be used to divide the sum. You will obtain the mean.
