The molarity of H3PO4 solution if 15.0 ml is completely neutralized by 38.5 ml of 0.15m naoh is calculated as follows
find moles of NaOH used = molarity x volume
= 38.5 x 0.15 = 5.775 moles
write the reacting equation
3NaOH + H3PO4 = Na3PO4 + 3H2O
from the equation the reacting ratio between NaOH to H3Po4 which is 3:1 the moles of H3PO4 is therefore = 5.775/3 = 1.925 moles
molarity of H3PO4 is therefore = moles /volume
= 1.925/15 = 0.128 M
Answer: The millimoles of sodium carbonate the chemist has added to the flask are 256
Explanation:
Molarity is defined as the number of moles dissolved per liter of the solution.
To calculate the number of moles for given molarity, we use the equation:
.....(1)
Molarity of 
solution = 1.42 M
Volume of solution = 180.0 mL
Putting values in equation 1, we get:
Thus the millimoles of sodium carbonate the chemist has added to the flask are 256.
The total energy can be found by adding the different energies:
628 + 15,600 + 712
= 16.94 kJ
Answer:
104.84 moles
Explanation:
Given data:
Moles of Boron produced = ?
Mass of B₂O₃ = 3650 g
Solution:
Chemical equation:
6K + B₂O₃ → 3K₂O + 2B
Number of moles of B₂O₃:
Number of moles = mass/ molar mass
Number of moles = 3650 g/ 69.63 g/mol
Number of moles = 52.42 mol
Now we will compare the moles of B₂O₃ with B from balance chemical equation:
B₂O₃ : B
1 : 2
52.42 : 2×52.42 = 104.84
Thus from 3650 g of B₂O₃ 104.84 moles of boron will produced.
