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Lab Safety
The Metric System, Scientific notation, SIG FIGS
Chemical and Physical Changes
Elements, Compound, and Mixtures
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100

This piece of safety equipment protects your eyes from chemical splashes and flying particles.

What are safety goggles?

100

Write in scientific notation: 0.000450

 4.5 × 10⁻⁴

100
Explain the difference between chemical and physical changes.
Chemical changes: Two substances combine to create a new substance with different properties. Physical changes: Two substances are combined and each retains the same properties as the elements that make it up.
100
Define element
Element: a pure substance that is composed of only one type of atom. It cannot be broken down into simpler substances.
100
What happens when you place an object with a density of 2.5g/cm3 into water that has a density of 1.0g/mL? Explain why your answer would happen.
The object would sink because it has a higher density than the water.
200

Before starting any laboratory activity, this document should be read carefully to understand the procedure and potential hazards.

What are the lab instructions (or lab procedure)?

200

Convert 750 milliliters to liters

0.75 L

200
List four different evidences of a chemical change.
Change in color, odor, the release of energy or heat, light, sounds, and bubbling or fizzing.
200

Name 3 Compounds and their chemical formulas

Water H2O, Carbon Dioxide CO2, Methane CH4

200
List 3 physical changes.
Melting, mixing, separating, crushing, tearing, solid to liquid, liquid to gas, evaporating, dissolving, , grinding, and sanding.
300

If a chemical is accidentally spilled on your skin, this is the first thing you should do.

What is immediately flush the area with water and notify the teacher?

300

How many significant figures are in the number 0.00720?

3 significant figures

300
List four physical properties of matter.
physical properties of matter: color, shape, size, state, melting point, freezing point, boiling point, malleability (the ability to bend), density, volume, mass, or solubility (the ability to dissolve)
300

This type of matter is made of two or more different elements that are chemically bonded together, such as water (H₂O)

What is a compound?

300

Write a chemical formula that represents a compound and one that represents an element.

Element: C, H, Cl. Compound:  C6H12O6, H2O, CO2, CH4.

400

This piece of equipment is used to put out small fires and should only be used if instructed by the teacher.

What is a fire extinguisher?

400

Round 0.0045678 to 3 significant figures.

0.00457

400

Changes of state of matter are considered which type of change? Explain why.

Changes of state are PHYSICAL changes because the substance still has the same chemical properties, just in a different form. Water is still water (H2O) when it is a liquid, solid (ice), or gas (water vapor).

400

How is a compound different from a mixture?

Mixtures are physically combined and can be separated, compounds chemically combined and can be separated by chemical means

400
Jack has a rock. The rock has a mass of 6g and a volume of 3cm3. What is the density of the rock?
D = m/v so the density of the rock equals 6/3. Density = 2 g/cm3.
500

A student notices broken glass on the lab table after an experiment. According to proper lab safety procedures, what should they do?

What is notify the teacher?

500

A scientist measures a mass as 2.34 g and a volume as 1.2 mL. When dividing these values to calculate density, the answer should be reported with how many significant figures.

 2 significant figures

500
Why are chemical properties harder to observe than physical properties?
Chemical properties change the substances identity or makeup.
500

A sample contains iron filings and sand mixed together. A magnet can be used to separate the iron from the sand. This type of matter is an example of a ______.

What is a heterogenous mixture?

500
True or False: The total mass of reactants is ussually greater than the total mass of products
FALSE The total mass of the reactants equals the total mass of the products.