Answer:
Explanation:
Electron configurations and the periodic table. Elements are placed in order on the periodic table based on their atomic number, how many protons they have. In a neutral atom, the number of electrons will equal the number of protons, so we can easily determine electron number from atomic number.
Answer:
0.776 ×10²³ atoms of oxygen
Explanation:
Given data:
Mass of Al₂CO₃ = 10.0 g
Number of atoms of oxygen = ?
Solution:
Number of moles of Al₂CO₃:
Number of moles = mass/molar mass
Number of moles = 10.0 g/233.99 g/mol
Number of moles = 0.043 mol
1 mole of Al₂CO₃ contain 3 mole of oxygen.
0.043 ×3 mol = 0.129 mol
Number of atoms of oxygen:
1 mole contain 6.022×10²³ atoms
0.129 mol × 6.022×10²³ atoms / 1mol
0.776 ×10²³ atoms of oxygen
Answer:
1. d. 84g
2. c. 77.4%
Explanation:
1. Based on the reaction 2 moles of Na produce 2 moles of NaCl.
The moles of Na (22.99g/mol) in 33g are:
33g * (1mol / 22.99g) = 1.435 moles Na = 1.435 moles NaCl must be produced.
The mass of NaCl is (Molar mass: 58.44g/mol):
1.435moles * (58.44g / mol) = 84g
d. 84g
2. Percent yield is defined as 100 times the ratio between actual yield (65g) and theoretical yield (84g). The percent yield is:
65g / 84g * 100 =
c. 77.4%
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