a) The least number of decimal points is 0 so you should round the answer to 43.
b) The least number of significant figures is 2 so round to 7.3
c)The least number of decimal places is 1 so round to 225.7
d) The least number of significant figures is 3 so round to 92.0
e) The least number of significant figures is 3 so round to 32.4
f) The least number of decimal places is 0 so round to 104m^3
Basically, for addition and subtraction round to the least number of decimal places found in the factors, and for multiplication and division round to the least number of significant figures found in the factors.
1 pm = 10∧-10 cm
Therefore, 230 pm is equivalent to 2.3 ×10∧-8 cm.
Atom is in the shape of a sphere,
The volume of a sphere is given by 4/3πr³
Thus, volume of the atom = 4/3π( 2.3 ×10∧-8)³
= 4/3 (3.142 ×12.167×10∧-24
= 5.096 ×10∧-23 cm³
but 1m³= 1000000cm³
Therefore, the volume of the atom = 5.096 ×10∧-29 m³
A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.0°C. Which of the following is its molecular formula?
1) NO2
2) N3O6
3) N2O5
4) N2O4
5) NO
Answer:
2Sb^(+3) (aq) + 3S^(-2) (aq) = Sb_2•S_3
Explanation:
First of all, let us balance the equation to give;
2Sb(OH)3 (s) + 3Na2S (aq) = Sb2S3 + 3NaOH
Now, we can observe the presence of positive Sodium ions (Na+) and negative hydroxyl ions (OH-) on both left and right sides of the equation.
Now, the two ions will cancel out. These ions are not really involved in the overall reaction and thus do not require being written in the overall equation. Hence, the overall net ionic reaction can now be written as:
2Sb^(+3) (aq) + 3S^(-2) (aq) = Sb_2•S_3
