Chemistry Answers

give one advantage of using nano particles in sun creams

Explain the chemistry behind the buffer system in blood.

The isotope strontium-90 is produced during the testing of nuclear weapons. If 100.0mg of strontium-90 was released in the atmosphere in 1960, how much of the radioisotope remains 85 years later? The half-life of strontium-90 is 29 years. Show all your work.

1.Calculate the freezing point of solution containing 0.600 kg of CHCl3 and 42.0 g of Eucalyptol (C10H18O) , a fragrant substance found in the leaves of eucalyptus tree. Kf for CHCl3 is 4.68°C/molal and normal freezing point is -63.5°C.

1.Calculate the freezing point of solution containing 0.600 kg of CHCl3 and 42.0 g of Eucalyptol (C10H18O) , a fragrant substance found in the leaves of eucalyptus tree. Kf for CHCl3 is 4.68°C/molal and normal freezing point is -63.5°C.

2.List the following aqueous solutions in order of their expected freezing points ( from lowest to highest) : 0.50 m CaCl2 ; 0.15 m NaCl ; 0.10 m HCl ; 0.050 m HC2H3O2 ; 0.10 m C12H22O11. Then explain the reason why you arrange it that way.

List the following aqueous solutions in order of their expected freezing points ( from lowest to highest) : 0.50 m CaCl2 ; 0.15 m NaCl ; 0.10 m HCl ; 0.050 m HC2H3O2 ; 0.10 m C12H22O11. Then explain the reason why you arrange it that way.

Calculate the solubility of Ca(OH)₂ in a 0.469M CaCl₂ solution at 31⁰C, given that the K_sp of Ca(OH)₂ is 4.96 X10^-6 at that temperature and give the answer in milli Molar units.

When one mole of nitrogen gas, N2, reacts with one mole of oxygen gas, O2, two moles of nitric

oxide, NO, are formed. In the process, 180.5 kJ of heat are required.

a. Write the thermochemical equation for the chemical reaction (Use two ways in writing the

equation)

b. What does the sign of ΔH indicate?

c. Is the reaction endothermic or exothermic? what happens to heat when the reaction takes

place?

d. If 3 moles of nitrogen gas, N2, are made to react with three moles of oxygen gas, O2, how

much heat is required in the process?

e. How much heat will be released if two moles of nitric oxide, NO, are broken down into one

mole of nitrogen gas, N2, and one mole of oxygen gas, O2?

Consider an acid-base reaction when Nitric acid is added to copper (11) hydroxide. What is the net ironic equation for this reaction

One mole nitrogen oxide, NO, reacts with oxygen gas to produce a brown gas. How many moles NO must react with excess oxygen to release 120kJ of

heat?