Other Chemistry Answers

Determine the limiting reactant when 4.2 mol Fe(OH)3 reacts with 6.5 mol H2SO4 in the following reaction.

2 Fe(OH)3 + 3 H2SO4 --> Fe2(SO4)3 + 6 H2O

Determine the limiting reactant when 4.2 mol Fe(OH)3 reacts with 6.5 mol H2SO4 in the following reaction.

2 Fe(OH)3 + 3 H2SO4 --> Fe2(SO4)3 + 6 H2O

1. calculate the number of moles of sodium carbonate present in 100cm³ of 2M solution
2.calculate the mass of sulphuric (iv)acid in 250cm3 of solution whose concentration is 0.25mole dm³
3. Calculate the number of moles present in 25cm³ of a 0.2M sodium hydroxide solution
Mass in grams present in 25cm³ of a 0.2M sodium hyroxide solution
4.calculate the number of moles of sodium chloride in 500cm³ of 3M sodium chloride solution
5.calculate the mass of calcium chloride required to make one litre of 0.2M calcium chloride
6.when 34.8g of potassium sulphate were dissolved in 500cm³ distilled water.calc a)the concentration of potassium sulphate b) molarity of the solution

A saturated solution of salt x contains 0.28g of the salt in 100cm³ of solution at 25 degrees Celsius what is the solubility of the salt x at this temperature (relative molecular mass of x = 56)

when 1 mole of barium sulfate was dissolved in water it resulted to a H of 0.52 KJ/mol. How much heat is absorbed when 450g if the compound is dissolved in water has zero effect

For the following nucleotides, identify the components and whether the nucleotide is found in DNA only, RNA only, or both DNA and RNA:
a.deoxyguanosine-5'- monophosphate (dGMP) b.adenosine-5'-monophosphate (AMP)

(b) The acid concentration is determined by titrating the sample with a 0.05 mol dm-3 sodium hydroxide solution.
10 cm3
of sodium hydroxide reacts completely with 5 cm3
of the sample. Given that the equation for the
reaction between sodium hydroxide and methanoic acid is
NaOH (aq) + HCOOH (aq) → HCOONa (aq) + H2O (l)

i. Suggest a suitable indicator for this titration.

ii. Calculate the concentration of the acid in the sample.

iii. Use your answer to (ii) above and the pH value of the sample to calculate the value of Ka for the acid.

1. One type of kidney stones is formed by the precipitation of calcium phosphate (Ca3(PO4)2), which has a Ksp of
1.3 x 10-32 at 25 C. A patient submitted a urine sample which contained concentrations of 1.2 x 10-4 mol dm-3 calcium
ions and 1.1 x 10-8 mol dm-3 phosphate ions.
(a) Write a balanced equation for the formation of calcium and phosphate ions from calcium phosphate.

(b) Write the expression for the solubility product constant for calcium phosphate.

(c) Calculate the ionic product of calcium phosphate in the patient's urine.

(d) State why kidney stones are likely to form in the patient's urine.

a) Use the following equation to explain how the aqueous hydrogen carbonate ion acts as a buffer.
HCO3
–
(aq) + H2O (l) H3O
+
(aq) + CO3
2– (aq)


(b) A buffer solution is made by adding 6.56 g of sodium ethanoate, CH3COONa, to 1 dm3
of 0.02 M ethanoic acid,
CH3COOH.
i. Calculate the concentration of the sodium ethanoate solution in mol dm-3
.
ii. Ka for ethanoic acid is equal to 1.8 x 10-5 mol dm-3
.
Write the expression for Ka and use it to calculate the pH of the buffer solution.
State any assumptions made in the calculation.

_1.ThehalflifeforthedecompositionofhydrogenperoxideH2O 2at40 0cis2.16x
10sec.Whatistherateconstantforthefirstorderdecompositionofhydrogen
peroxide? A.321second B.32.1x1010sec C.3.21x10 5sec D.32100sec