Answer: 19.4 g/cm3
Explanation: density is the relationship between mass over volume.
So density of gold is 15.7g/0.81cm3 = 19.4 g/cm3
Answer:
C. BF3
Explanation:
The boron in BF3 is electron poor and has an empty orbital, so it can accept a pair of electrons, making it a Lewis acid.
First, calculating the amount of zinc carbonate by multiplying the given mass of the ore by the percent zinc carbonate.
mass of zinc carbonate = (976 tons)(0.78)
= 761.28 tons
Then, calculate for %Zn in zinc carbonate
%Zn = ((65.38) / (125.39)) x 100%
% Zn = 52.141%
tons of Zn from the sample,
mass of Zn = (761.28 tons)(0.52141)
= 396.94 tons Zn
The number of moles hydrogen produced when 6 moles of sodium are used is calculated as below
2Na + 2H2O = 2NaOH +H2
by use of mole ratio between Na to H2 which is 2:1 the moles of H2 is therefore
= 6 x1/2 = 3 moles of H2
Answer:
Explanation:
AgNO3 + NaCl --> AgCl + NaNO3
Number of moles
AgNO3
= molar concentration * volume
= 1 * 0.01
= 0.01 mol
NaCl
= 0.01 * 1
= 0.01 mol.
By stoichiometry, 1 mole of silver nitrate reacted with 1 mole of NaCl. Therefore,
Number of moles of AgCl formed = 0.01 × 1
= 0.01 mol AgCl formed.
Heat absorbed by solution during precipitation:
Mass of solution = density × total volume
= 1 × 20
= 20 g.
q = m * Cp * (T2 - T1)
= 20 * 4.18 * (32.6 - 25.0)
= 635 J
Since 635 J was absorbed by the solution, the reaction released -635 J
So, Delta H = -635 J/0.01 mol
= -63500 J/mol
= -63.5 kJ/mol.
