The first person to answer these three questions the best, gets ten points!?

Question

1. Will freezing a mixture of salt and water seperate the two substances? Explain your answer please.

2. A teaspoon of instant coffee is placed in a cup of boiling water. Is this a mixture or a compound? Explain your answer please.

3. How can you seperate a mixture of sand, water, and gravel? Please explain a little.

Answer 1

Ahh, memories of physical science and chemistry classes:
1. Salt dissolves when placed in water. Freezing the mixture gives you frozen salt water. If, instead, you added heat to the water, the water would evaporate and leave salt particles behind.
2. A mixture is usually physically created and can be separated relatively easily. A compound is formed through a chemical reaction and typically has properties unique to either original ingredient. The instant coffee is dissolved, which is a physical reaction, and is therefore a mixture.
3. Sand, water, and gravel represent different sized matter: gravel is larger than both sand and water, sand is larger than water molecules, and water is the smallest item. You could sift the gravel from the sand and water, similar to how miners panned for gold. This you could then let the sand dry out, or sift with a much smaller screen designed to let water flow and capture sand.

Answer 2

1) Salt breaks down in water into Na and Cl ions. Only removing the water will seperate out the compounds again (so freezing won't work).

2) Compound = a chemical change creating a new chemical. Coffee, tea, Martini's etc.. are all mixtures. The basic materials don't change, they just get surrounded by water. Removal of the water gives you the same material again.


3) To seperate insoluable materials (ie things that don't dissolve completely in water like salt), you can use a many methods, with the easiest being a series of filters. A net mesh like you'd have on a screen door will let water and sand through, but not gravel. You'd then take the sand and water mixture and filter it through a smaller screen and you'd be left with sand on top of the filter and water below.

Answer 3

1- The salt will not be separated. To do that you need to heat or evaporate the water away.
2- Mixture. A compound changes the objects radically ie oxygen and hydrogen.
3- A large grit screen will eliminate the gravel
A smaller grit screen will get most of the sand.
If you spread out the sand on a concrete slab, allowing the rest of the water to evaporate you will succeed completely.

Answer 4

salt water is a solution and will freeze at 0* F it does not separate by freezing but can by boiling.

Water is alread a compound with coffee it becomes a mixture.. to seperate just boil the water and the coffee will be left

Heat the sand and gravel will remove the water... Use screens to separate the gravel from the sand

Answer 5

1. No the ice will trap the salt particles, but if you evaporate the water they will separate.

2. Mixture, this does not change the chemical make up of the water or the coffe

3. Let the water evaporate, then shake the sand and gravel, the sand will fall to the bottom and the gravel will rise to the top.

Answer 6

1. Freezing will not separate the substances.
2. Mixture because compounds involves more than two substances permanently being combined.
3. Boil the water out, then grate the sand out.

Answer 7

1. NO because water is a polar molecule and mixes with anything except lipids to create chemical bonding.

2. mixture because a compound is just two things that dont mix

3. drain the water to get the gravel
dry out the sand to seperate it from the water
if you need the water wet
use a grain seperator

Answer 8

1. I dk srry...
2. Its a mixture... A mixture is 2 things mixed together.... if you leave that coffee sit out for a long time the water and the coffee will seperate.....
3. I dk srry...

Answer 9

1/George Bush 2/Cardio Pulmanery Recusitation 3/Shrimp Maybe?

Answer 10

1. i dont know
2. mixture
3. filtration