Mixtures
I made two kool-aids. The first had 3 scoops of powder and 100mL of water. The second had 9 scoops of powder and 300mL of water. Which is more concentrated?
3/100=9/300
They are the same concentration.
What does it mean if a solution is saturated?
The solution can no longer dissolve any more solute.
What is a chemical change?
-A reaction that cannot be UNDONE and a NEW substance is created.
If something is more dense than a liquid it goes into, what will happen?
It will sink.
What is special about a solution compared to a mixture?
A solution is a mixture in which something DISSOLVES.
What are 2 ways we can make a solution less concentrated?
-More solvent.
-Less solute.
How do we know when a solution is saturated?
When we begin to see the solute collect at the bottom of the container.
A solution in a closed system weighs 150 grams before a chemical reaction. What is the mass of the solution after the chemical reaction?
150 grams. Since matter cannot be created or destroyed and it is in a closed system, the mass stays the same even if it looks different.
A student adds 10 grams of sugar and 25 grams of lemonade powder into 1000 mL of water. What is the mass of the solution?
10g + 25g + 1000g =1035 grams
A student mixes salt and water together. Their sibling believes that the salt has disappeared. How can the student show their sibling that the salt is still in the solution?
-she can compare the mass of the solution to an equal volume of water and show that it's more
-she can evaporate the water to show crystals
What are two ways we can make a solution more concentrated?
-Less solvent.
-More solute.
What is more soluble, salt or sugar?
Sugar. The solubility of salt is 17g. The solubility of sugar is 46g.
What is an example of a chemical change?
Burning wood, mixing vinegar and baking soda, rust on a nail.
If an object has the same density as a liquid, what will happen?
It will float in the middle of the solution.
40g + 30g + 20g = 90g
What is the relationship between density and concentration?
The more concentrated a solution is, the more dense it is.
I was running a lab and forgot to record how much solute I added to a solution. All of the solute dissolved. How can I find the mass of the solute?
1. Weigh the solution.
2. Subtract the mass of the water from the mass of the solution.
What is an example of a physical change?
Refrigerating juice, freezing water, melting ice, ripping paper...
You break a stick in half. The mass and the volume of the new pieces are exactly half of the original mass and volume. What will happen to its density?
Its density will stay the same because it is still the same material.
A student wants to separate a mixture of iron, salt, and sand. How would the student do this? Put the steps in order below.
___ Evaporate water
___ Add water
___ Use screen
___ Use filter
___ Use Magnet
_4_ Evaporate water
_2_ Add water
___ Use screen
_3_ Use filter
_1_ Use Magnet
I mix 4 spoons of sugar into 50mL of water. Each spoon weighs 2g. I let the solution sit in the sun. What will the mass of sugar be?
4spoons x 2g = 8g of sugar
A student mixes Epsom salts into 100 mL of water until the solution is saturated. She wants to know how many grams of Epsom salts it took to saturate 100 mL of water. What would she do?
1) Filter the solution.
2) Weight the solution.
3) Subtract 100g from the mass of the solution.
When two hydrogen atoms and one oxygen atom combine, it creates water. 2 H + O ----> H2O. What is the name of the theory that explains why there are the same number atoms on each side of the equation?
Conservation of Mass= matter cannot be created or destroyed. Atoms cannot just appear or disappear.
What science did Ms. Brody study in college?
Biology