What is the concentration in molarity of a solution that has 54.21g of calcium hydroxide dissolved in 560mL of water?
1 answer:
We know that Molarity = # mol/L
In the question, we are given grams - so we need to calculate the number of moles that we are dealing with. We can do this by first finding out what the molecular formula of calcium hydroxide is:
This means that we have 1 calcium and 2 hydroxides.
We can find the number of moles by taking the grams given divided by the molar mass of the molecule. We can find the molar mass of the molecule by taking each atomic mass of each atom (found on the periodic table) and adding them together:
Ca = 40.08g
O = 15.999g
H = 1.008g
We have 1 calcium, 2 oxygens, and 2 hydrogens. So let's add the atomic masses together:
40.08 + 2(15.999) + 2(1.008) = 74.094g
Now that we have the molar mass, we can find the number of moles due to already knowing the given amount in the question:
54.21g/74.09g = 0.73 moles of
Now that we know the number of moles, we can solve for the molarity; The other part of the question gives us 560 mL of water - but this can quickly be converted to liters by moving the decimal to the left 3 places => 0.560 L
Knowing all of this information, we can plug it into the molarity equation:
Molarity = 0.73 mol/0.56 L
Molarity = 1.30
The molarity of the solution is 1.3 M.
In the question, we are given grams - so we need to calculate the number of moles that we are dealing with. We can do this by first finding out what the molecular formula of calcium hydroxide is:
This means that we have 1 calcium and 2 hydroxides.
We can find the number of moles by taking the grams given divided by the molar mass of the molecule. We can find the molar mass of the molecule by taking each atomic mass of each atom (found on the periodic table) and adding them together:
Ca = 40.08g
O = 15.999g
H = 1.008g
We have 1 calcium, 2 oxygens, and 2 hydrogens. So let's add the atomic masses together:
40.08 + 2(15.999) + 2(1.008) = 74.094g
Now that we have the molar mass, we can find the number of moles due to already knowing the given amount in the question:
54.21g/74.09g = 0.73 moles of
Now that we know the number of moles, we can solve for the molarity; The other part of the question gives us 560 mL of water - but this can quickly be converted to liters by moving the decimal to the left 3 places => 0.560 L
Knowing all of this information, we can plug it into the molarity equation:
Molarity = 0.73 mol/0.56 L
Molarity = 1.30
The molarity of the solution is 1.3 M.
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Answer:
Final temperature: 659.8ºC
Expansion work: 3*75=225 kJ
Internal energy change: 275 kJ
Explanation:
First, considering both initial and final states, write the energy balance:
Q is the only variable known. To determine the work, it is possible to consider the reversible process; the work done on a expansion reversible process may be calculated as:
The pressure is constant, so: (There is a multiplication by 100 due to the conversion of bar to kPa)
So, the internal energy change may be calculated from the energy balance (don't forget to multiply by the mass):
On the other hand, due to the low pressure the ideal gas law may be appropriate. The ideal gas law is written for both states:
Subtracting the first from the second:
Isolating :
Assuming that it is water steam, n=0.1666 kmol
ºC