An aqueous solution of cobalt(II) nitrate has a concentration of 0.471 molal.
The percent by mass of cobalt(II) nitrate in the solution is %.
0.471 m means 0.471 mols Co(NO3)2 in 1 kg solvent.
How many g Co(NO3)2 is 0.471 mols? That's g = mols x molar mass = ? = approx 86 grams Co(NO3)2
Total mass of the solution then is approx 86 + 1000 = approx 1086g total.
% = (g solute/total grams solution)*100 = ?
0.471 m means 0.471 mols Co(NO3)2 in 1 kg solvent.
How many g Co(NO3)2 is 0.471 mols? That's g = mols x molar mass = ? = approx 86 grams Co(NO3)2
Total mass of the solution then is approx 86 + 1000 = approx 1086g total.
% = (g solute/total grams solution)*100 = ?
i don't get this what you mean????
? means I assume you can do what comes before the ?
g = mols x molar mass.
You want to know grams Co(NO3)2. You know mols Co(NO3)2. You can look up the molar mass Co(NO3)2.
So to obtain grams (which you must do to solve the problem) you take mols (0.471) from above and multiply by molar mass (which I didn't bother to addup since you can do that). mols x molar mass = grams but I didn't multiply for you.
An aqueous solution of manganese(II) chloride has a concentration of 0.392 molal.
The percent by mass of manganese(II) chloride in the solution is
%.
To find the percent by mass of cobalt(II) nitrate in the solution, we need to understand what a molal concentration is and how it is related to percent by mass.
Molality (molal concentration) is a measure of the number of moles of solute (in this case, cobalt(II) nitrate) dissolved in exactly one kilogram (1000 grams) of solvent (in this case, water). It is denoted by the symbol "m".
To calculate the molality of a solution, we use the following formula:
Molality (m) = moles of solute / mass of solvent in kg
Given that the concentration of the cobalt(II) nitrate solution is 0.471 molal, it means that there are 0.471 moles of cobalt(II) nitrate dissolved in one kilogram of water.
To find the percent by mass, we need to know the molar mass of cobalt(II) nitrate. The molar mass can be calculated by adding up the atomic masses of all the elements in the formula:
Co(NO3)2
Cobalt (Co) has a molar mass of 58.933 g/mol
Nitrate (NO3) has a molar mass of 62.004 g/mol (14.007 g/mol for nitrogen + 3 * 16.00 g/mol for oxygen)
Molar mass of cobalt(II) nitrate = (1 * 58.933 g/mol) + (2 * (14.007 g/mol + 3 * 16.00 g/mol))
Now, we can calculate the percent by mass using the following formula:
Percent by mass = (mass of solute / mass of solution) * 100
Since the solvent here is water and it has a density of 1 g/mL, we can assume 1 kilogram of water is equal to 1000 grams.
Therefore, the mass of solute (cobalt(II) nitrate) in one kilogram (1000 grams) of solution is equal to the number of moles of cobalt(II) nitrate multiplied by its molar mass:
Mass of solute = (m * molar mass of cobalt(II) nitrate)
Finally, we can calculate the percent by mass using the formula mentioned earlier:
Percent by mass = (mass of solute / mass of solution) * 100 = [(m * molar mass of cobalt(II) nitrate) / (m * molar mass of cobalt(II) nitrate + mass of water)] * 100
Substituting the given values:
Percent by mass = [(0.471 molal * molar mass of cobalt(II) nitrate) / (0.471 molal * molar mass of cobalt(II) nitrate + 1000 g)] * 100
By plugging in the values and calculating the expression, we can find the percent by mass of cobalt(II) nitrate in the aqueous solution.