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Answers to Readers' Questions on Chemistry:
Mixture Types
The following 7 comments and questions have been sent in. They are listed according to date.
List of first 10 items
- Who invented chemistry?
- Is milk, vanilla, and sugar a colloid or solution?
- Isn't paint a solution?
- Mixing carbon disulphide with iron and sulphur
- What is the mobile phase in chromatography?
- Is a seashell a mechanical mixture or a solution?
- Paints are liquids that become a solid
Who invented chemistry?
Question
October 12, 2009
sir i want to know the history of chemistry?
means when it is invented? who is the inventor?
shahebaz - India
18485
Answer
Chemistry started with the ancient people, who mixed materials together to cook and make paints. There was no one inventor of the science. Many people contributed to chemistry over the centuries.
Is milk, vanilla, and sugar a colloid or solution?
Question
May 5, 2009
if i had a mixtured that was milk, vanilla, and sugar. would that be a colloid or solution. i knowe it is not suspension
meme - USA
17707
Answer
Milk is a colloid. Vanilla and sugar would form a solution within the milk, but I believe the combination would still be a colloid.
Isn't paint a solution?
Question
November 1, 2008
I teach 3rd grade and in the Harcourt science book on the chapter on Physical Changes in Matter, there is a picture of red and yellow paint on a plate that is being stirred together. The caption identifies this as a mixture. I thought this would be a solution. Why do they call this a mixture?
- USA
16720
Answer
In a solution, one material is dissolved within the other, such that they cannot be readily separated. Salt dissolved in water is a good example. You cannot separate the salt and water by mechanical means. You'd have to boil off the water to get the salt.
In a mixture, the materials can be separated by mechanical means.
If you mixed red and yellow paint together thoroughly, you would get orange-colored paint. But if you let the paint sit for long enough in a bucket, the colors would eventually separate into red and yellow sections. You could also use a centrifuge to separate the colors, since the color particles probably have a slightly different weight.
Mixing carbon disulphide with iron and sulphur
Question
July 1, 2008
What will happen when you mix carbon disulphide with iron and sulphur ppowder?
Goh - Malaysia
16159
Answer
The sulphur will dissolve in the carbon disuplhide, leaving the iron filings that you can separate out. But you cannot filter out the sulphur, because it is now in a solution.
What is the mobile phase in chromatography?
Question
February 13, 2008
what is a mobile phase?
Is brass a homogeneous or a heterogeneous mixture?
What does a true solution consist of?
What does paper chromatography employ?
Kevin - USA
15345
Answer
Mobile phase is seen in chromatography, where a sample is being separated and the solvent moves the sample through the column.
Brass is an alloy of copper and zinc. If mixed properly, it would be homogeneous.
Is a seashell a mechanical mixture or a solution?
Question
January 30, 2008
Is a seashell a mechanical mixture or a solution?
Anne - Canada
15250
Answer
A seashell is a solid. Mixtures involve particles that can be easily. Solutions involve liquids.
Paints are liquids that become a solid
Question
November 26, 2007
Paints are liquid when applied,but need to be solid on the wall,why?
Natasha - United Kingdom
14855
Answer
Paints are a mixture of solid paint particles in a solution of a liquid such as linseed oil, water or something material. Once the liquid paint is put on the all, the liquid evaporates and leaves the paint particles attached to the wall. Of course these particles are dense in a multiple layers to seem like a solid material on the wall.
If the paint did not dry, it could easily be rubbed off.
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