Chemistry Unit 1 test.

Directions: For the following reaction, fill in the missing information. (2 pts) Iron + Sulfur 🡪 Iron (II) sulfide

30 g 10g 40 g

While measuring the mass of a 5.0g weight, you observe measurements of 3.4g, 5.4g, and 7.3g. These measurements do not have good precision nor

Accuracy (G)

In the scientific method, _____ is the step in which experimental results are used to decide the validity of each hypothesis.

Analysis (B)

In a compound the elements are _____ together, whereas in a mixture the substances are blended together.

Bonded (M)

A _____ property of water is that it is unreactive with oil.

Chemical (F)

Scientific notation includes two parts, the _____ and the power of 10.

Coefficient (A)

When measuring off any instrument, you must measure all certain digits off the instrument plus one extra _____ digit.

Estimated (L)

____ is an example of a physical change.

Freezing (O)

In the gas state, a substance will have a(n) _____ volume.

Indefinite (V)

An exact number has an _____ amount of significant figures.

Infinite (C)

In the _____ state, substances have a definite volume and an indefinite shape.

Liquid (G)

Anything that has mass or volume is called _____.

Matter (S)

Phase changes are classified as _____ changes.

Physical (D)

How close multiple measurements are to each other is called

Precision (D)

While observing a chemical reaction, you say to your lab partner "the outside of the beaker is very hot." This is an example of a _____ observation.

Qualitative (H)

The measurement of 13.5° Celsius from a thermometer is a _____ observation.

Quantitative (i)

Perform the following calculations, and round to the correct number of significant figures on the smaller lines. On the larger lines, please write the answer in scientific notation! CAREFUL - WATCH THE TYPE OF CALCULATION YOU ARE PERFORMING. (10pts) Rounded answer: Answer in scientific notation: a) 20 + 2.1 = b) 3400 / 0.25 c) 30,000 x 0.034

Rounded Answer: Answer in Scientific Notation 20 + 2.1 = 22 2.2x101 3400 / 0.25 14000 1.4x104 30,000 x 0.034 1000 1x103

d) 540.34 - 14.0 = 526.3 5.263x102 e) 6.3 x 2.903 = 18 1.8x101

Rounded Answer: Answer in scientific notation 526.3 5.263x102 18 1.8x101

Identify how many significant figures there are in the following numbers: (6pts) a) 230mL b) 5009cm3 c) 0.0030mm d) 1.40g e) 2.000km f) 3404 pens

a) 2 b) 4 c) 2 d) 3 e) 4 f) infinite

Directions: Identify each of the following as an element (E), heterogeneous mixture (HE), compound (C), or homogeneous mixture (HO). (6 pts) a) taco b) penny c) copper d) water e) Trix Cereal f) potassium

a) HE b) HO c) C d) C e) HE f) E

Directions: Identify each of the following as a physical change (PC) or chemical change (CC). (6 pts) a) dissolving salt b) mixing sand and water c) rusting iron d) boiling water e) digesting taco bell f) melting butter

a) PC b) PC c) CC d) PC e) CC f) PC