CI Inv 1-2 Review

In class, a group of students added water to two mystery substances and allowed the water to evaporate. They recorded their observations in their notebooks. Compare one student's observations to the key that shows the crystal formation of four substances. KEY (shows crystal formation of Alum, Citric Acid, Epsom Salts, Sodium Chloride) Student Notebook Entry: Sample B: The crystals look like cubes and seem smaller than the crystals of other samples. The crystals don’t seem to stick together. (Dissolved in water: Yes) Identify each sample and give evidence to support your claim. Sample B = ________ What evidence supports your claim? ____________________________

• Sample B = Sodium chloride Evidence: The sodium chloride crystals look cube-like, smaller, and more separated, as described in the observations.

• Sample B = Alum Evidence: The alum crystals are not cube-like and tend to clump together, which does not match the observations.

• Sample B = Citric acid Evidence: The citric acid crystals are not cube-shaped and usually appear as irregular shapes, which does not match the observations.

• Sample B = Epsom salts Evidence: The Epsom salts crystals are needle-like, not cube-shaped, which does not match the observations.

Tags

NGSS.MS-PS1-2

What is the difference between the substances represented by the symbols Co and CO?

• They are two different ways to represent the element cobalt.

• One is the symbol for an element, and one is a formula for a compound.

• Co represents the element cobalt, and CO represents the element copper.

• They represent two substances, each made up of two elements.

Tags

NGSS.MS-PS1-1

What was Mendeleyev's purpose for reorganizing the periodic table?

• He wanted to fit all the elements on one page instead of in a long line.

• He wanted to put elements with similar characteristics in the same column.

• He wanted to order the elements from the lightest to the heaviest.

• He wanted to put all the metals on one side of the table and gases on the other.

When Mendeleyev changed the layout, there were gaps where no known element fit. How did the gaps help scientists look for undiscovered elements? Check ALL that apply.

• They indicated where new elements should be found.

• The gaps showed scientists what elements could not exist.

• The gaps predicted the characteristics of new elements.

• The gaps predicted the mass of the new elements.

A group of students mixed two liquids together. After leaving the mixture alone for ten minutes, two separate layers formed. They recorded information about each substance in a table. Chose ALL answers that show evidence of a chemical reaction.

• Liquid 1 and layer B have the same boiling point.

• Liquid 1, liquid 2, and layer A are clear; layer B is red.

• The combined mass of liquids 1 and 2 is the same as the combined mass of layer A and layer B plus any gas that escaped the system.

• The substance bubbled after liquids 1 and 2 were mixed together.

• Two liquid substances existed before and after they were mixed.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A group of students mixed two liquids together. After leaving the mixture alone for ten minutes, two separate layers formed. They recorded information about each substance in a table. (Refer to the diagram and table provided.) a. Consider the properties of the substances before and after they were mixed, and make a claim of whether a chemical reaction occurred.

• A chemical reaction occurred because the substances are all the same before and after.

• A chemical reaction occurred because of the layers and color change.

• It was only a physical change because the substances are all the same before and after.

• It was a physical change because of the layers and color change.

Tags

NGSS.MS-PS1-2

A Chemical Change is one that

• Changes the molecules of the matter

• Does not change the molecules of the matter

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A change in the state of matter is an indicator of a:

• Chemical Change

• Physical Change

Tags

NGSS.MS-PS1-4

Cutting paper would be a physical change because:

• Cutting Changes the molecules of the paper

• cutting only change the size and shape of the paper

• A new substance was produced by cutting

Burning wood is an example of:

• Chemical Change

• Physical Change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5