Answer:
1. How many ATOMS of boron are present in 2.20 moles of boron trifluoride? atoms of boron.
2. How many MOLES of fluorine are present in of boron trifluoride? moles of fluorine.
Explanation:
The molecular formula of boron trifluoride is
.
So, one mole of boron trifluoride has one mole of boron atoms.
1. The number of boron atoms in 2.20 moles of boron trifluoride is 2.20 moles.
The number of atoms in 2.20 moles of boron is:
One mole of boron has ----
atoms.
Then, 2.20 moles of boron has
-
2. Calculate the number of moles of BF3 in 5.35*1022 molecules.

One mole of boron trifluoride has three moles of fluorine atoms.
Hence, 0.0888moles of BF3 has 3x0.0888mol of fluorine atoms.
=0.266mol of fluorine atoms.
I bottle:
250 * 150mg = 37500mg
If 37500mg ------- cost ------- <span> $2.95
so 1mg ------- cost ------- x
x = 1mg*</span> $2.95 / 37500mg = $7,87*10⁻⁵
II bottle
125 * 200mg = 25000mg
If 25000mg ---------- cost ---------- <span>$3.50
so 1mg ---------- cost ---------- x
x = 1mg* </span>$3.50 / 25000mg = $0,00014=$1,4*10⁻⁴
$7,87*10⁻⁵ < $1,4*10<span>⁻⁴
</span>
1st bottle is better bargain cause 1mg of aspirin its cheaper than in 2nd.
Answer: The new pressure of the gas in Pa is 388462
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,

where,
= initial pressure of gas at STP = 
= final pressure of gas = ?
= initial volume of gas = 700.0 ml
= final volume of gas = 200.0 ml
= initial temperature of gas = 273 K
= final temperature of gas = 
Now put all the given values in the above equation, we get:


The new pressure of the gas in Pa is 388462
Answer: 63.26%
Explanation:
If we let the abundance of the first isotope be x, then:

Which is equal to <u>63.26%</u>