Answer:
63.05% of MgCO3.3H2O by mass
Explanation:
<em>of MgCO3.3H2O in the mixture?</em>
The difference in masses after heating the mixture = Mass of water. With the mass of water we can find its moles and the moles and mass of MgCO3.3H2O to find the mass percent as follows:
<em>Mass water:</em>
3.883g - 2.927g = 0.956g water
<em>Moles water -18.01g/mol-</em>
0.956g water * (1mol/18.01g) = 0.05308 moles H2O.
<em>Moles MgCO3.3H2O:</em>
0.05308 moles H2O * (1mol MgCO3.3H2O / 3mol H2O) =
0.01769 moles MgCO3.3H2O
<em>Mass MgCO3.3H2O -Molar mass: 138.3597g/mol-</em>
0.01769 moles MgCO3.3H2O * (138.3597g/mol) = 2.448g MgCO3.3H2O
<em>Mass percent:</em>
2.448g MgCO3.3H2O / 3.883g Mixture * 100 =
<h3>63.05% of MgCO3.3H2O by mass</h3>
There are two valence electrons in a single atom of magnesium.
Typically kinetic energy changes is passed through objects when it crashes
Answer:
The correct answer is 399.8 ppm
Explanation:
A concentration in parts per million (ppm) is equal to:
Solute: Cd; Mass = 180 mg x (1 g/1000 mg) = 0.18 g
Solvent: Water ; Mass= 450.0 g x (1 kg/1000 g) = 0.45 kg
We have the following total mass of solution:
Mass of solution = Mass of solute + Mass of solvent = 0.18 g + 450 g = 450.18 g = 0.45018 kg
Finally, we divide the <u>mass of solute (in mg)</u> into the <u>mass of solution (in kg)</u> to obtain the ppm (in mg/Kg):
ppm = 180 mg/0.45018 kg = 399.8 mg/Kg = 399.8 ppm
