How many atoms of each element are chemical formula: 3K2O3. How many atoms of each element are chemical formula: 2H3NCH3Br.
How many atoms of each element are chemical formula: 4Ar2CO3.
Each of them are different questions pls help me

In 3K2O3 - 6 K atoms, 9 O atoms

In 2H3NCH3Br - 12 H atoms, 2 N atoms, 2 C atoms, 2 Br atoms

In 4 Ar2CO3 - 8 Ar atoms, 4 C atoms, 12 O atoms

Explanation:

All you need to do is multiply the coefficient by the number of each atom in the compound. For example, H3NCH3Br has 1 nitrogen, 1 carbon, 1 bromine, and 6 hydrogens. If you have 2H3NCH3Br, just multiply all those numbers by 2.

b. th3 n4zc4 pl4t3 15 c0nv3rg1ng w1th the s0uth 4m3ric4n pl4t3.

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.