Answer:
5.83 g
Explanation:
First, you must start with a balanced equation so you can see the mole ratios.
NaOH + H₃BO₃ --> NaBO₂ + 2H₂O
You can see that it takes 1 mole of sodium hydroxide to form 1 mole of sodium borate. 1:1 ratio
Now you must calculate how many moles of NaOH 35.47 g equals.
Na = 22.99 amu
O = 15.99 amu
H = 1.008 amu
NaOH = 39.997 amu
35.47 g ÷ 39.997 amu = 0.08868 moles of NaOH
Since it's a 1:1 ratio, the same number of moles of NaBO₂ is created. Now you must convert moles to grams.
Na = 22.9 amu
B = 10.81 amu
2 O = 31.998 amu
NaBO₂ = 65.798 amu
0.08868 moles x 65.798 = 5.83 g
Mass percentage of a solution is the amount of solute present in 100 g of the solution.
Given data:
Mass of solute H2SO4 = 571.3 g
Volume of the solution = 1 lit = 1000 ml
Density of solution = 1.329 g/cm3 = 1.329 g/ml
Calculations:
Mass of the given volume of solution = 1.329 g * 1000 ml/1 ml = 1329 g
Therefore we have:
571.3 g of H2SO4 in 1329 g of the solution
Hence, the amount of H2SO4 in 100 g of solution= 571.3 *100/1329 = 42.987
Mass percentage of H2SO4 (%w/w) is 42.99 %
Answer:
6 grains
Explanation:
The equation of the reaction between NaOH and aspirin is;
C9H8O4(aq) + NaOH (aq) ------>C9H7O4Na(aq) + H2O(l)
Amount of NaOH reacted = concentration × volume = 0.1466 M × 14.40/1000 L = 2.11 × 10^-3 moles
Given that aspirin and NaOH react in a mole ratio of 1:1 from the balanced reaction equation above, the number of moles of aspirin reacted is 2.11 × 10^-3 moles
Hence mass of aspirin reacted = 2.11 × 10^-3 moles × 180.2 g/mol = 0.38 g
If 1 grain = 0.0648 g
x grains = 0.38 g
x= 0.38 g/0.0648 g
x= 6 grains
