Troubleshooting Chemistry Questions: CaCO3, I2, C2+

• ~angel~
In summary, 20.0g of CaCO3 will remain unreacted at equilibrium if it is sealed in a 10.0L container and heated to 800°C.
~angel~
Just having trouble again with a few questions.

1.Calcium oxide (lime) is a white crystalline solid with a melting point of
2572c. It is manufactured by heating limestone, coral, sea shells or
chalk, which are mainly CaCO3, to drive off carbon dioxide, according to
the following reaction.

CaCO3(s) --> CaO(S) + CO2(g) Kp= 1.16 atm at 800c

If 20.0g of CaCO3 were sealed in a 10.0L container and heated to 800c, what
percentage of CaCO3 would remain unreacted at equilibrium?

2.A saturated solution of iodine in water contains 0.330g I2 per litre, but
more than this amount can dissolve in a potassium iodide solution because
of the following equilibrium.

I-(aq) + I2(aq) <--> I3- (aq)

A 0.100 M KI solution dissolves 12.5g of I2 per litre, most of which is
converted to I3-(aq). Assuming that the concentration of I2(aq) in all
saturated solutions is the same, calculate the equilibrium constant for
the above reaction.

I know Kc= [I3-]/[I-][I2], but I don't know where to go from there.

3. What is the longest wavelength of light that the ground state C2+ ion will
absorb? For this question, an MO diagram is given with energy in electron volts. I'm assuming you need to convert the energy into joules (multiply by 1.602*10^-19) and use E=hc/lambda, but I don't know where to measure the energy from.

Any help would be great.

~angel~ said:
1.Calcium oxide (lime) is a white crystalline solid with a melting point of
2572c. It is manufactured by heating limestone, coral, sea shells or
chalk, which are mainly CaCO3, to drive off carbon dioxide, according to
the following reaction.

CaCO3(s) --> CaO(S) + CO2(g) Kp= 1.16 atm at 800c

If 20.0g of CaCO3 were sealed in a 10.0L container and heated to 800c, what
percentage of CaCO3 would remain unreacted at equilibrium?

How many moles of CO2 would produce 1.16 atm at 800°C in 10L, ignoring the volume of 20 g of CaCO3?

Ok, I get it. Thanks.

Does anyone know how to do questions 2 and 3 (particularly 2)?

1. What is the chemical formula for calcium carbonate (CaCO3)?

The chemical formula for calcium carbonate is CaCO3, which represents one calcium atom, one carbon atom, and three oxygen atoms bonded together.

2. How can I identify iodine (I2) in a solution?

Iodine can be identified by its deep purple color in solution. It can also be confirmed by adding a small amount of starch solution, which will turn the solution blue-black in the presence of iodine.

3. What does the "C2+" notation mean in a chemistry question?

The "C2+" notation refers to a cation, or a positively charged ion, with a charge of +2. This indicates that the ion has lost two electrons and has a net positive charge.

4. How can I calculate the molar mass of calcium carbonate (CaCO3)?

The molar mass of calcium carbonate can be calculated by adding the atomic masses of each element in the compound. The atomic mass of calcium is 40.08 g/mol, carbon is 12.01 g/mol, and oxygen is 16.00 g/mol. Therefore, the molar mass of CaCO3 is 100.09 g/mol.

5. What is the role of calcium carbonate (CaCO3) in the environment?

Calcium carbonate plays a crucial role in the environment as it is a major component of many natural structures, such as shells, coral reefs, and limestone. It also helps regulate the pH of soil and water, and is used as a dietary supplement for humans and animals.

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