Answer:
Freezing T° of solution = - 8.98°C
Explanation:
We apply Freezing point depression to solve this problem, the colligative property that has this formula:
Freezing T° of pure solvent - Freezing T° of solution = Kf . m
Kf = 1.86°C/m, this is a constant which is unique for each solvent. In this case, we are using water
m = molality (moles of solute / 1kg of solvent)
We convert the mass of solvent from g to kg
1.5 g . 1kg/1000g = 0.0015 kg
We convert the mass of solute, to moles. Firstly we make this conversion, from mg to g → 450mg . 1g/1000mg = 0.450 g
0.450 g. 1mol / 62.07g = 7.25×10⁻³ moles
Molality → 7.25×10⁻³ mol / 0.0015 kg = 4.83 m
- Freezing T° of solution = 1.86°C /m . 4.83 m - Freezing T° of pure solvent
-Freezing T° of solution = 1.86°C /m . 4.83 m - 0°C
Freezing T° of solution = - 8.98°C
I don't know sorry just google it
Answer:
ΔE = 5.02 x 10⁻¹⁹ j
Explanation:
ΔE (photon) = h·f = (6.63 x 10⁻³⁴ j·s)(7.57 x 10¹⁴ s⁻¹) = 5.02 x 10⁻¹⁹ j
h = Planck's Constant = 6.63 x 10⁻³⁴ j·s
f = frequency (given) = 7.57 x 10¹⁴ s⁻¹
Answer:
Chemical reaction B governs the process
Explanation:
The first part of the question asks to convert the mass of the calcium carbonate given to number of moles.
Mathematically;
Number of moles = mass/molar mass
Molar mass of CaCO3 = 100 g/mol
So the number of moles of CaCO3 will be 2.49/100 = 0.0249 moles
The second part of the question asks to convert the mass of carbon iv oxide to moles of carbon iv oxide
Mathematically;
That is same as ;
Number of moles = mass/molar mass
molar mass of CO2 is 44 g/mol
Number of moles of CO2 = 1.13/44 = 0.0256 moles
Now, if we compare the values of these number of moles, we can see that there are almost equal.
What this means is that the number of moles of calcium carbonate reacted is equal to the number of moles of carbon iv oxide produced.
So what we conclude here is that we have an equal mole ratio between the two compounds.
So the reaction that would be the correct answer will present equal number of moles of carbon iv oxide and calcium carbonate
Thus, we can see that reaction B is the one that governs this process as it is the only reaction out of the three options that present the two compounds with equal number of moles.
