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If 15.65 mL of aq. HCl is required to neutralise 20.00 mL of the sodium carbonate
solution from question 4 above, what is the molarity of the aq. HCl? (Show all steps in
your calculation as set out below.)
(a). Write the reaction equation for the titration.
(b). Calculate the number of moles of Na2CO3 (standard solution) used in the titration.
(c). Using the balanced reaction equation, find the number of moles of HCl that
reacted.
(d). Calculate the molarity of the HCl solution.
A compound has mass percentage of 65.450%carbon and 5.492%Hydrogen and 29.060%Oxygen. It has a molar mass of approximately 110grams per mol. Determine the molecular formula of the compound
Using the localized electron model, decribe the bonding in hydrogen cyanide and phosgene
A sample of ammonium sulphate was heated with 100.0 mL of 0.50mol/L aqueous sodium hydroxide. To ensure that all the ammonium sulphate reacted, an excess of sodium hydroxide was used. Heating was continued until all of the ammonia had been driven off as a gas. The unreacted sodium hydroxide remaining in the solution required 27.3 mL of 0.600mol/L hydrochloric acid for neutralization. Calculate the concentration of the ammonium salt.
Use the localised electron model to describe the bonding in hydrogen cyanide and phosgene (COCl2)
Calculate the ΔH of the following problems:
1) How many joules are required to raise the temperature of 450 mL of water from 30°C to 100°C?
2) The specific heat of copper metal is 0.385 J/g °K. How many kJ of heat are needed to raise the temperature of 1.1 kg block of copper from 27.5°C to 50°C?
A new sunscreen has been developed that is supposed to be more effective at preventing sunburn. 30 participants spray one arm with the new formula, and the other arm with the leading formula. After 4 hours in the sun, their skin is evaluated for any redness
1. A feedstuff weighing 2 g and moisture content at 5%. When estimating the crude protein, use 82 ml of HC1 (0.01 N) (Plank volume = zero). Calculate
i. The percentage of crude protein base on dry matter.
ii. The percentage of crude protein base on natural (fresh) material.
iii. The percentage of crude protein base on organic matter, when crude ash in the feedstuff is 0.3 g.
Draw the molecular orbital diagram for F2 molecule. Calculate the bond order and predict its magnetic property
For each of the following molecules, write the Lewis structure(s), predict the molecular structure (including bond angles), give expected hybrid orbitals on the central atom, and predict the overall polarity.
a. OF2 b. AsF5 c. IF5
