1. Which of the following is an example of a direct observation?

a. Measuring the amount of rain that falls in a 24-hour period in a rain gauge.

b. Estimating the number of rabbits in your garden by examining the number of plants eaten

c. Determining how many people ate the school pizza by looking at trays to see if people threw away their
pizza.

d. Compiling survey results to
learn how people feel about a

2. Which of the following is an example of a good hypothesis?

A. The vinegar is the acid and the soap is the base.

B. I think the glow sticks will brighter in the hot water.

C. when placed in hot water, sugar cubes will dissolve more slowly that granulated sugar

3. Which of the following correctly matches the observation with the description?

a. The car is silver in color; quantitative

b. The car is has 3 foot pedals ; qualitative

C. The car has 4 doors; qualitative

d. The car has 1 steering wheel; quantitative -

4. Which of the following metric conversions is correct?
a. 1 meter = 1000 km
b. 1 cm = 10 dm
C. 1 mm = 10 cm
d. 1 cm = 10 mm

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )