Experiment 2 pre lab and lab

3. How could you separate magnesium chloride, MgCl2, from silver chloride, AgCl?

Silver chloride its at the bottom so you can just filter it out. AgCl is insoluble, while MgCl2 is solible. Add water, Decantarjon to remove SiO2 and boil off to separate TeO2.

1. Could the separation in this experiment have been done in a different order? For example, if the mixture was first extracted with water and then both the extract and the insoluble residue were heated to dryness, could you determine the amounts of NaCl, NH,CI, and Sio, originally present? Why or why not?

Yes it could. If the sand (SiO2) is filtered off first and the remaining solution is evaporated to dryness, the 2 salts remaining can still be separated by subliming the NH2Cl

How could you separate zinc chloride from SiO2?

Zinc Chloride is soluble, Therefore it will be dissolved in the filtrate and the SiO2 will be the residue.

1. Classify each of the following as a pure substance or a mixture; if it is a mixture, state whether it is heterogeneous or homogeneous: (a) concrete, (b) tömato juice, (c) marble, (d) seawater, and (e) iron.

homogeneous: sea water, tomato juice. Heterogeneus: marble, concrete. Iron is a pure substance.

Suggest a way to determine whether a colorless liquid is pure water or a salt solution without tasting it.

see which liquid conducts electricity. A solution with electrolytes such as NaCl would conduct; pure water would not. Boil all the water away but if there is residue, it is most likely a salt solution.

Define the process of sublimation.

when a solid passes directly into gaseous state and back to solid state with out appearance ot liquid state.

Why is the NaCl extracted with water three times as opposed to only once?

Get the max amount of NaCl out of the mixture.

9. How could you separate a mixture of acetone and a-naphthol? Consult Table 2.1 for physical properties.

A-napthol is insoluble in cyclohexane and acetone is soluble. You can remove a-naphtol by filtering it from cyclohexane acetone mixture.

How could you separate lauric acid from a-naphthol? (See Table 3.1.) page 36

Add Cyclohexane to the mixture, a-naphtol is insoluble with cuclohexane then filter out lauric acid.

A student found that her mixture was 13% NH,CI, 18% NaCl, and 75% SiO,. Assuming that her calculations are correct, what did she most likely do incorrectly in her experiment?

Added too much water to evaporate out.

How does this experiment illustrate the principle of conservation of matter?

All of the original sample should be recovered. The sum of NH4Cl, SiO2, and NaCl should equal the total mass of the sample with in experimental error.

How do decantation and filtration differ? Which should be faster?

Decantarion is when a liquid is poured away from a solid. filtration is when a liquid is poured through a filter and a solid is left afterwards. Decantarion is faster because it doesnt involve the use of another substance.

A mixture was found to contain 1.05 g of Sio2, 0.69 g of cellulose, and 1.82 g of calcium carbonate. What percentage of calcium carbonate is in the mixture?

Mass of the calcium carbonate, mass of all 3 compounds. 1.82g/3.56g X100=51

What distinguishes a mixture from an impure substance?

If a substance contained primarily one compenent, it's an Impune substance. If it has a similar amounts of several components. It is a mixture

Why should you never place a hot object on the pan of a balance?

It created a buoyancy effect and will disappear or have a reduce mass.

2. How could you separate barium sulfate, BaSO,, from NaCl?

Use water to disole NaCl, filter out BaSO4.