Sodium and Chlorine combine to form table salt. Given the chemical reaction, how many grams of 2Na + Cl2 would be required to produce 4 grams of table salt?

Summarize the Venn diagram.

A group of chemistry students had to identify six white powders. The students used a variety of tests to identify the powders. They computed the density of each powder. They checked to see if any dissolved in water. One of the powders did not dissolve in water and they thought it was cornstarch. Someone knew that cornstarch felt slippery and reacted with iodine. The students put a few drops of iodine on each white powder. One powder turned black; they guessed that it was cornstarch. They heated the powders in a Bunsen burner flame to see if any would melt. One did and they guessed it might be a sugar.

Which test result indicated a chemical change had taken place?

Maria and Carla were hiking when Maria tripped, fell, and sprained her ankle. Carla took out the first-aid kit and unwrapped a cold pack. Carla popped a vial that was inside the cold pack. The pack began to get icy cold and Carla applied the pack to Maria's ankle.

What kind of reaction occurred in the cold pack? What evidence supports your answer?

What element behaves MOST like magnesium (Mg)?

During a physical science lab investigating chemical reactions, several students placed a 30g antacid tablet in a 30g zip-lock bag. They recorded the masses of the tablet, and the bag. Then they added 50 grams of water and quickly sealed the bag. The tablet began to fizz and soon disappeared. The bag was filled with gas. If the mass of the liquid after the reaction is completed is still 50 grams, how much gas is produced?

Matter may be classified as a pure substance or a mixture. Where on the Venn diagram would you insert the term "pure substance"?

Ms. Crawford gave the following instructions to her science class:

• Place an empty water bottle on the table and remove the lid. Carefully pour 10 ml of vinegar into the bottle.

• Open up the mouth of the balloon and have you lab partner spoon 1 teaspoon of baking soda into the balloon.

• Without spilling any of the baking soda, stretch the mouth of the balloon over the mouth of the bottle.

• Turn the balloon completely upright so that the baking soda inside the balloon pours into the bottle with the vinegar. Watch!

The baking soda looked like it dissolved in the vinegar. Sarah and Connor watched as the balloon expanded and filled with a gas. Was this a physical or chemical reaction and why?

Your teacher hands you a clear liquid and asks you to classify it. You and your lab partner perform a sample of tests and get the following results:

1. After evaporation, no substances remain. 2. No residue remains in paper after filtering. 3. Boiling point is low (compared to water).

Where on the Venn Diagram would you place your mystery substance?

Describe the energy change in the particles of a substance during melting.

When a substance such as ice melts, its temperature increases. Describe what happens to the arrangement of the water molecules as the temperature increases.

Ben and Sam were conducting experiments on physical and chemical changes in science class. First they added some salt to water and stirred it up until the salt dissolved. "That's a physical change" Ben said. "And that's a solution which is a mixture", added Sam. Next they added an anti-acid tablet to some water. The water began to fizz and bubble. The beaker got cooler. "That's a physical change too," Ben noted. "No, it's not," responded Sam. Who is correct and where should the contents of the beaker be placed in the Venn diagram?

The molecule arrangement of ice, water and steam are very different. _______ has the most ordered arrangement, ______ has the next most orderly arrangement, and ___________ has the least orderly arrangement of molecules.

Mrs. Smith is demonstrating a chemical change for her class. She places 15 grams of baking soda into a beaker. Next she adds 15 grams of vinegar to the same beaker. When the two compounds make contact, they bubble and fizz a great deal. She places the beaker on the balance and notes that the mass of the solution in the beaker is less than the expected 30 grams.

Why is the mass of the solution in the beaker less than 30 grams?

From the list below, determine which properties are for compounds.

I. It takes a large amount of energy to separates the elements of a compound. II. The proportions of the elements in a compound are always fixed.

III. It is easy to separate the elements of a compound.

IV. The elements/components of a compound do not retain their individual properties.

The circle on the left shows a magnified view of a very small portion of liquid water in a closed container. What would the magnified view show after the water evaporates?

Which image(s) would be considered pure substances?

I. An atom is the smallest unit of an element and a molecule is made up of two or more atoms chemically bonded together.

II. An atom is indivisible and a molecule can be broken down into atoms.

III. An atom is the smallest unit bonded together and a molecule is made up of elements.

IV. An element is the smallest unit of an atom and a molecule is made up of two or more metal and non-metal atoms chemically bonded together.

Which conclusion(s) best elaborate on the difference(s) between an atom and a molecule?

Elaborate on the reason(s) that matter is said to move even as in a solid state.

I. O2 is chemically bonded together.

II. O2 is divisible.

III. Oxygen is a nonmetal.

IV. The natural state of oxygen is as a diatomic gas.

Which conclusion can be drawn from these statements about O2?

From the list below, identify which situation(s) contain chemical changes.

I) A pot of water is being heated on a stove. Bubbles form and condensation appears on the lid of the pot.

II) A translucent, blue copper (II) sulfate solution is mixed with another solution and changes to a translucent lighter blue color. III) Ammonium nitrate solid dissolves in water and feels very cold.

IV) Red and blue paint are mixed together and the color purple appears.

Elaborate what knowing that carbon-14 has an atomic number of 6 tells us about the atom.

A student draws a picture of the products and reactants of a chemical reaction. What, if anything, is wrong with the drawing?

A flask with vinegar in it has a mass of 160 grams. A balloon with baking soda in it has a mass of 40 grams. The balloon is attached to the flask to seal the opening and the vinegar and baking soda mixes. The balloon inflates to a large volume. What will the total mass of the balloon and flask be after the balloon inflates? Explain.