1.) is157.7 g
<span>moles Fe = 209.7 g/ 55.847 g/mol=3.75
the ratio between Fe and CO is 2 : 3
moles CO = 3.75 x 3 /2 =5.63
mass CO = 5.63 mol x 28.01 g/mol=157.7 g
2.) is </span><span>1.06 moles
</span>48.7/23 = 2.12 moles sodium
<span>2.12/2 x 24 = 25.44dm^3 hydrogen = 1.06 moles </span>
1.06 X 6.02x10^23 = 1.204x10^24 molecules of hydrogen.
3.) is 91.8
<span>8.3 moles H2S x (2 moles H2O / 2 moles H2S) = 8.3 moles H2O = theoretical amount produced. </span><span>8.3 moles H2O x (18.0 g H2O / 1 mole H2O) = 149 g H2O produced theoretically. </span><span>% yield = (actual amount produced / theoretical amount) x 100 = (137.1 g / 149 g) x 100 = 91.8 </span>
Answer:
V2 = 12 L
Explanation:
<u>Given the following data;</u>
Initial volume = 2L
Initial pressure = 3 atm
Final pressure = 0.5 atm
To find the new volume V2, we would use Boyles' law.
Boyles states that when the temperature of an ideal gas is kept constant, the pressure of the gas is inversely proportional to the volume occupied by the gas.
Mathematically, Boyles law is given by;
Substituting into the equation, we have;



<em>V2 = 12L</em>
<em>Therefore, the new volume is 12 Liters. </em>
Answer:
We have 1.361 moles in the sample
Explanation:
Mass of iron = 76.02g
Molar mass of iron = 55.845 g/ mole ( This we can find in the periodic table, and menas that 1 mole of iron has a mass of 55.845 g).
To calculate the number of moles we will use following formula:
moles (n) = mass / molar mass
moles iron = 76.02g / 55.845 g/ mole
moles iron = 1.36127 moles
To use the correct number of significant digits we use the following rule for multiplication and division :
⇒ the number with the least number of significant figures decides the number of significant digits.
⇒76.02 has 4 digits ( 2 after the comma) and 55.845 has 5 digits (3 after the comma).
⇒ this means 1.361 moles
We have 1.361 moles in the sample
Explanation:
1) Initial mass of the Cesium-137=
= 180 mg
Mass of Cesium after time t = N
Formula used :
Half life of the cesium-137 =
= initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope
= rate constant

Now put all the given values in this formula, we get
Mass that remains after t years.

Therefore, the parent isotope remain after one half life will be, 100 grams.
2)
t = 70 years


N = 35.73 mg
35.73 mg of cesium-137 will remain after 70 years.
3)


N = 1 mg
t = ?

t = 224.80 years ≈ 225 years
After 225 years only 1 mg of cesium-137 will remain.
(23.1 + 5.61 + 1.008) × 7.6134 × 8.431
= 29.718 × 7.6134 × 8.431
=1907.55608
The equation is solved in the manner that the term in the bracket is added first then mutiplication is done as according to Bodmas rule, if an equation contains brackets that need to be solved first then other operation that is division,multiplication, addition and subtraction are performed from left to right .