Chemistry Answers

1. Solid calcium carbonate is synthesized from calcium oxide powder and carbon dioxide gas.

2. The reaction between calcium carbide (kalburo, CaC2) and water forms acetylene (C2H2) and

calcium hydroxide, Ca (OH)2 .

3. The combustion of the mineral pyrite (FeS2) in oxygen gas produces another mineral hematite

(Fe2O3) and sulfur dioxide.

4. The oxidation of phosphine (PH3) to phosphorus pentoxide (P2O5) is given by the chemical

equation: PH3 + O2 → P2O5 + H2O

5. Thermite welding is an exothermic reaction,which produces molten iron that permanently

binds metals as it cools. The process does not require heat or electricity. Aluminum powder is

simply mixed with ferric oxide powder. The reaction is accompanied by a release of heat, and produces aluminum oxide and molten iron.

If 6.5 gram of magnesium ribbon reacts completely with hydrochloric acid how many grams of H2 will be liberate (H=1,Mg=24)

Find degree of hydrolysis (DOH), hydrolysis constant (Kh) and P

H

of a salt HCOOK

(0.001M). if Ka for weak acid HCOOH is 10-4

.

The reaction between calcium carbide (kalburo, CaC₂) and water forms acetylene (C_{2}*H_{2}) and calcium hydroxide [Ca(OH) 2 ].

What are the empirical and molecular formulas of a compound that is 40.27 % potassium, 26.78 % chromium, and 32.95 % oxygen? The molar mass of the compound is 194.2 g/mol.

Find the volume of 0.8 moles of a gas that has a pressure of 100 kPa at 27°C.

Calculate the molar mass of acetaminophen (C_{8}*H_{9} * N * O_{2}) an over-the-counter pain reliever also known as paracetamol.

Lithium has two known stable isotopes- lithium-6 and lithium-7. Lithium-6 has an isotopic mass of 6.015 amu and percent abundance of 7.59%; lithium-7 has a mass of 7.016 amu at 92.41 % abundance. Calculate the average atomic mass of lithium.

How many grams of C5H8 are needed to produce 216 g of H20

Choose 5 of listed forms of enthalpy of reaction given above and give 1 example of chemical reaction each form with it's brief explanation why it is categorized to that form enthalpy.