Chemistry Answers

1.The waxy coating on the surface of apple skins contains an alkane with 27 carbon atoms. What is the molecular formula of this alkane?

2.The waxy coating that covers tobacco leaves contain a straight chain alkane having 31 carbons. How many hydrogens does this alkane contain?

What is the molecular formula for a hydrocarbon with 10 carbons that is (a) completely saturated (b) alkene (c) alkyne

Draw and explain the vapour pressure curve of a solution showing positive deviation from Raoult's law

3. If iron filings were an impurity present along with the ASA in this

experiment, at which point in the recrystallization procedure would they

be removed completely from the ASA? (What slide numbers show this

procedure?)

4. What is the purpose of adjusting the polarity in slide 19 of the slide

presentation?

5. Would benzoic acid dissolve better in water, or in ethanol? Explain why

using the concepts discussed in this laboratory.

1. In a final very careful and correct recrystallization from acetone, benzoic acid (pure mp 122-122.3°C) was melted on a melting point machine immediately after vacuum filtration and washing, and found to have a melting point of 116-121°C. Why is the melting point not 122-122.3°C? Assume that there are no solid compounds present other than benzoic acid present, and suggest what may be present to affect melting point, and what role that presence does.

2. What are 2 advantages of using gravity filtration over vacuum filtration when removing a solid impurity from a hot mixture? 

reaction with Caco3 and Ezyme produce

Caffeine (C 8 H 10 N 4 O 2 ), is a stimulant found in coffee, tea, colas and energy drinks. It is

used to restore mental alertness or wakefulness during fatigue or drowsiness. Caffeine is

also found in some headache and migraine medications. Solve for its percent

composition.

How can determined of Sulfate in detergent washing powder?

reaction with Caco3 and Ezyme produce

1. Provide the possible candidate ion/s for the primary adsorbed layer of a colloid formed when small amounts of silver nitrate is added to a solution of potassium chromate by accounting the following five factors: solubility, concentration, common ion, ion charge and ion size. Write the colloid formula.