They are odourless, colourless monatomic gases with full outer shells
Answer:- 
molecules.
Solution:- The grams of tetrabromomethane are given and it asks to calculate the number of molecules.
It is a two step unit conversion problem. In the first step, grams are converted to moles on dividing the grams by molar mass.
In second step, the moles are converted to molecules on multiplying by Avogadro number.
Molar mass of 
= 12+4(79.9) = 331.6 g per mol
let's make the set up using dimensional analysis:
= molecules
So, there will be molecules in 250 grams of .
Answer:
H2O is a compound because its a main constitute of earths hydrosphere
Answer:
The correct answer to this problem is B. 7.0 X 10^-8 meters
Explanation:
To solve this problem, we have to use the following equation:
c = λν, or speed of light = wavelength*frequency
If we substitute in the values we are given by the problem, we get:
3.00 * 10^8 m/s = (4.3 * 10^15 Hz)*(wavelength)
wavelength = 6.98 * 10^-8 m
Since the given value has 2 significant figures, our answer should similarly include two significant figures since the operation in the problem was multiplication.
Therefore, the answer is B. 7.0 X 10^-8 meters.
Hope this helps!
Answer:
A is your answer i believe
Explanation:
