The empirical formula is K₂O.
The empirical formula is the <em>simplest whole-number ratio</em> of atoms in a compound.
The <em>ratio of atom</em>s is the same as the <em>ratio of moles</em>.
So, our job is to calculate the <em>molar ratio</em> of K to O.
Step 1. Calculate the <em>moles of each element
</em>
Moles of K = 32.1 g K × (1 mol K/(39.10 g K =) = 0.8210 mol K
Moles of O = 6.57 g O × (1 mol O/16.00 g O) = 0.4106 mol 0
Step 2. Calculate the <em>molar ratio of each elemen</em>t
Divide each number by the smallest number of moles and round off to an integer
K:O = 0.8210:0.4106 = 1.999:1 ≈ 2:1
Step 3: Write the <em>empirical formula
</em>
EF = K₂O
Answer : The time passed in years is 
Explanation :
Half-life = 5730 years
First we have to calculate the rate constant, we use the formula :



Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = ?
a = let initial amount of the reactant = X g
a - x = amount left after decay process = 
Now put all the given values in above equation, we get


Therefore, the time passed in years is 
Answer: A. They absorb radiation given off by the earth.
Explanation: Green house gases are gases that have the capability of trapping the heat energy from the sun in our environment. These special attribute of these gases is what keeps our environment warm and sustain life as we know it. Example of Green House Gases include: carbon dioxide, water vapour and methane.
The emission of the light waves ..................... which means that THE TROUGHS OF ONE WAVE AND THE CREST OF ANOTHER overlap.
When the trough and the crest of wave overlap, it results in constructive interference and the amplitude of the two waves are added together to form a larger amplitude.<span />
Answer:
B) 3rd
Explanation:
The 3rd ionization energy represents the removal of electrons from a filled core shell.
The electron configuration of calcium is [Ar]4s^2. Hence after the removal of the second electron from the 4s^2 orbital, a lot of energy is required to remove an electron from the next completely filled core shell. This is the highest successive jump in ionization energy. The other options in the question deal with electrons found on the same shell.