Jack

Chemistry Benchmark 1 Review Sheet

1. Interpret the following graph in terms of overall trend vs. short term trends. Overall trend rises while short term trends vary.

2. A student conducted an experiment to see the effects of salt water on plant growth. Why should she have more than one plant for each concentration of salt water? Use more than one plant to verify the results

3. You are to measure 25.0 g of Sand. The closest you can get is 24.62g.

a. Calculate the percent error. 1.52 %

b. What could be some possible causes of the percent error? Incorrect units being measured, balance not calibrated, air blowing on object, etc…

Magnesium Ribbon

Synonyms: magnesium ribbon, magnesium wire, magnesium powder

Molecular formula: Mg

CAS No: 7439-95-4

EC No: 231-104-6

Appearance: silver or grey rod, turnings or ribbon

Melting point: 650 C

Boiling point: 1107 C

Vapour density:

Vapour pressure: 1 mm at 621 C

Specific gravity: 1.73

Flash point: 634 C (closed cup)

Explosion limits:

Autoignition temperature: 510 C

Stable. Reacts violently with halogens, chlorinated solvents, chloromethane. Air and moisture sensitive. Incompatible with acids, acid chlorides, strong oxidizing agents. Highly flammable.

Harmful if swallowed or inhaled. Severe irritant. Vesicant.

Wear Safety Glasses

4. Using the information above, A) name 3 physical characteristics of Mg ribbon and B) if burned would there be any gas given off, if so what is the proper way to detect it?

A) melting point: 650 °C, boiling point 1107°C, specific gravity 1.73

B) yes, you must waft the vapor towards you.

5. Using the information above, what personal protective equipment would you need? Goggles, Mask

6. If you were to measure the length of a foot ruler and get values of

12.01 in, 12.00 in, 11.99 in, and 12.00 in

Would these measurements be precise, accurate, both or neither? Why? They are accurate and precise. Accurate because they are the...