Chemistry Answers

Q8.

Calculate the standard free energy change for the combustion of methane at 25^oC. Assume that all reactants and products are gases. Provide an answer correct to 3 significant figures. Do not use scientific notation or include units to report your answer.

Q.6

Liquid bromine (Br₂) boils at 58.8^oC and has a standard enthalpy of vaporization equal to 29.6 kJ/mol. Calculate the entropy change when 159.8 g of bromine vaporizes. Provide an answer correct to 3 significant figures.

What is the change in the internal energy of a system in which 66.1 kJ of heat is transferred to the surroundings while the surroundings do 44.0 kJ of work on the system? Provide an answer that is correct to 3 significant figures. 

Two small conducting and identical spheres A and B have charges -25 nC and +15 nC, respectively. They are separated by a distance of 0.02 m. (a) What is the magnitude of the electric force between the two spheres? Is this force attractive or repulsive? (b) The spheres are then allowed to touch each other and then separated. What is the magnitude of the force between the two spheres? Is this a repulsive force or an attractive force?

Two small conducting and identical spheres A and B have charges -25 nC and +15 nC, respectively. They are separated by a distance of 0.02 m.

How many millimoles of KSCN is in 750 mL of 3.25×10-3 M solution?

How many moles of carbon are in 333 mg of CaC2O4. 

Find the number of Na+ ions in 2.92 g of Na3PO4

1.It is a measure of how equally the electrons in a bond are distributed between the two atoms involved in a covalent bond.

A. polarity   C. ionization energy

B. octet rule    D. electron affinity 

2.The reaction of water with alkene to produce an alcohol is a/an ______ reaction. 

A. Addition    C. Combustion

B. Condensation    D. Saponification 

3. The organic starting materials for the preparation of an ester could be_________

A. an acid and alcohol   C. a ketone and alcohol

B. water and oxygen     D. alkane and aldehyde

4. Ammonia (NH₃), can be considered a Lewis base because it can donate what?

A. electrons   C. protons

B. hydronium ions   D. hydroxide ions 

5. In the ground state of a cobalt atom there are _____ unpaired electrons and the atom is _____.

A. 3, paramagnetic

C. 2, diamagnetic

B. B. 5, paramagnetic

D. 0, diamagnetic

6.Which of the following bond is the strongest?

A. carbon – hydrogen bond C. carbon – carbon triple bond

B. carbon – nitrogen bond  D. carbon – carbon single bond 

1. A pill weighing 325mg contains Captopril, a medication for high blood pressure. What is the concentration of Captopril in ppm?
2. A patient is given 1000mL of 5 percent glucose C6H12O6 solution intravenously in a 12 hour period. How many grams of glucose did the patient receive per hour?