(1) How many grams of copper, cu are there in 2.55 mol of cu? (2) Determine the percent composition of each of the following (a) ethylalcohol CH3CH2OH. (b) vitamin C, ascorbic acid C6H8O6. (c) Coteine, C18H21NO3. (3) A 27.5g sample of a compound containing carbon and hydrogen contains 5.5g of hydrogen. What is the empirical formula of this compound. (4) How many moles of gallium chloride are formed by the reaction of 1.5mol of HCL according to the following equation. 2Ga + 6HCL = 2GaCl3 + 3H2
To answer your questions, we will go step by step:
(1) To determine the number of grams of copper (Cu) in 2.55 mol of Cu, we need to use the molar mass of copper. The molar mass of copper is 63.55 g/mol.
To calculate the grams of copper, we can use the formula:
grams = moles * molar mass
Substituting the given values:
grams = 2.55 mol * 63.55 g/mol
Calculating further:
grams = 162.1755 g
Therefore, there are approximately 162.18 grams of copper in 2.55 mol of copper.
(2) Percent composition refers to the percentage of each element in a compound.
(a) To find the percent composition of ethyl alcohol (CH3CH2OH), we need to calculate the molar mass of each element and then divide it by the molar mass of the entire compound, then multiply by 100.
Molar mass of C = 12.01 g/mol
Molar mass of H = 1.01 g/mol
Molar mass of O = 16.00 g/mol
Total molar mass of compound = (12.01 * 2) + (1.01 * 6) + 16.00 = 46.07 g/mol.
The percent of each element in ethyl alcohol is then:
% C = (12.01 g/mol / 46.07 g/mol) * 100
% H = (1.01 * 6 g/mol / 46.07 g/mol) * 100
% O = (16.00 g/mol / 46.07 g/mol) * 100
(b) To find the percent composition of vitamin C, ascorbic acid (C6H8O6), follow the same steps as in part (a).
(c) To find the percent composition of codeine (C18H21NO3), follow the same steps as in part (a).
(3) To determine the empirical formula of a compound, we need to find the ratio of the elements present. In this case, we are given the mass of carbon and hydrogen.
Given:
Mass of compound = 27.5 g
Mass of hydrogen = 5.5 g
The remaining mass (27.5 g - 5.5 g = 22 g) is the mass of carbon.
Next, we need to convert these masses into moles, using the molar mass of each element:
Molar mass of C = 12.01 g/mol
Molar mass of H = 1.01 g/mol
Hence, the number of moles of carbon = 22 g / 12.01 g/mol ≈ 1.83 mol.
The number of moles of hydrogen = 5.5 g / 1.01 g/mol ≈ 5.45 mol.
Next, we divide each mole value by the smaller mole value (in this case, carbon) to get the simplest, whole-number mole ratio.
Dividing both moles by 1.83 mol:
Carbon: 1.83 mol / 1.83 mol ≈ 1
Hydrogen: 5.45 mol / 1.83 mol ≈ 2.98 ≈ 3
The empirical formula is CH3, indicating that the compound contains 1 carbon and 3 hydrogen atoms.
(4) To find the number of moles of gallium chloride (GaCl3) formed by the reaction of 1.5 mol of HCl, we need to use the balanced chemical equation and the stoichiometry of the reaction.
The balanced equation is: 2Ga + 6HCl = 2GaCl3 + 3H2.
According to the stoichiometry, for every 6 moles of HCl, 2 moles of GaCl3 are formed.
Therefore, using the mole ratio, we can calculate the number of moles of GaCl3:
moles of GaCl3 = (1.5 mol HCl / 6 mol HCl) * 2 mol GaCl3
Calculating further:
moles of GaCl3 = 0.5 mol
Thus, 1.5 mol of HCl would produce 0.5 mol of GaCl3.