Okay, to do this you have to work with the relative molecular mass (RMM). You can get this from looking at the periodic table.
The RMM for the whole molecule is:
58.933 + (2 x 35.453) + (12 x 1.008) + (6 x 15.9994) = 237.96
Then you work out the RMM for water:
(2 x 1.008) + 15.9994 = 18.0154
As there are 6 moles of water in this molecule then multiply the RMM of H2O by 6 = 108.0924
Finally, divide the total H2O RMM by the total molecule RMM and multiply by 100 to get a percentage:
(108.0925 / 237.96) x 100 = 45.42%
You can split the process in two parts:
1) heating the liquid water from 10.1 °C to 25.0 °C , and
2) vaporization of liquid water at constant temperature of 25.0 °C.
For the first part, you use the formula ΔH = m*Cs*ΔT
ΔH = 30.1g * 4.18 j/(g°C)*(25.0°C - 10.1°C) = 1,874 J
For the second part, you use the formula ΔH = n*ΔHvap
Where n is the number of moles, which is calculated using the mass and the molar mass of the water:
n = mass / [molar mass] = 30.1 g / 18.0 g/mol = 1.67 mol
=> ΔH = 1.67 mol * 44,000 J / mol = 73,480 J
3) The enthalpy change of the process is the sum of both changes:
ΔH total = 1,874 J + 73,480 J = 75,354 J
Answer: 75,354 J
Hey there!
It is evident that the problem gives the mass of the bottle with the calcite, with water and empty, which will allow us to calculate the masses of both calcite and water. Moreover, with the given density of water, it will be possible to calculate its volume, which turns out equal to that of the calcite.
In this case, it turns out possible to solve this problem by firstly calculating the mass of calcite present into the bottle, by using its mass when empty and the mass when having the calcite:
Now, we calculate the volume of the calcite, which is the same to that had by water when weights 13.5441 g by using its density:
Thus, the density of the calcite sample will be:
This result makes sense, as it sinks in chloroform but floats on bromoform as described on the last part of the problem, because this density is between 1.444 and 2.89. g/mL
Learn more:
Regards!
Answer:
The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.
Answer:
V₁ = 0.342 M
Explanation:
Given data:
Volume of HClO₄ = 15.00 mL
Volume of NaOH = 25.64 mL
Molarity of NaOH = 0.2000 M
Molarity of HClO₄ = ?
Solution:
Formula:
M₁V₁ = M₂V₂
V₁ = M₂V₂ /M₁
V₁ = 0.2000 M ×25.64 mL /15.00 mL
V₁ = 5.128 M. mL /15.00 mL
V₁ = 0.342 M
