I need your help) 1. The number of each kind of atom of the molecules involved in a reaction will NOT change as reactants form into products

a. True

b. False

2. Which of the following properties do Alkali Metals and Alkali Earth Metals have in common?

a. high melting points

b. low density

c. low melting points

d. malleable (can easily be bent)

3.The Law of Conservation of Mass states that (in a closed system) matter is neither created nor destroyed.

a. True

b. False

4.On the periodic table, elements with similar properties are arranged in

a. In Periods

b. In Groups

c. By Color

d. By Symbol

5.On the periodic table, elements with similar properties are arranged in

In Periods

In Groups

By Color

By Symbol

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

it takes on an electronical energy