Asample of gold (au) has a mass of 72.04 g.

a) calculate the number of moles of gold (au) in the sample. show your work and highlight your final answer.

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b) a sample of gold (au) has a mass of 72.04g. calculate the number of atoms of gold (au) in the sample. (use your answer from part a.) show your work and highlight your final answer.

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question 2 a sample of sodium chloride (nacl) has a mass of 16.55 g.
a) calculate the number of moles of nacl in the sample. show your work and highlight your final answer.

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b) a sample of nacl (sodium chloride) has a mass of 16.55g. calculate the number of moles of na (sodium). calculate the number of moles of cl (chlorine). (hint; you can use your answer from part a as your starting point.) show your work and highlight your final answer.

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c) a sample of nacl (sodium chloride) has a mass of 16.55g. calculate the number of atoms of na (sodium). calculate the number of atoms of cl (chlorine). (hint; you can use your answer from part b as your starting point.) show your work and highlight your final answer.
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question 3 a sample of table sugar (sucrose, c12h22o11) has a mass of 5.432 g.

a) calculate the number of moles of c12h22o11 in the sample. show your work and highlight your final answer.

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b) a sample of table sugar (sucrose, c12h22o11) has a mass of 5.432 g. calculate the number of moles carbon. calculate the number of moles hydrogen. calculate the number of moles oxygen. (hint: you can use your answer from part a as your starting point.) show your work and highlight your final answer.

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c) a sample of table sugar (sucrose, c12h22o11) has a mass of 5.432 g. calculate the number of atoms carbon. calculate the number of atoms hydrogen. calculate the number of atoms oxygen. (hint: you can use your answer from part b as your starting point.) show your work and highlight your final answer.

calculation

Question 1 : A) 0.365 mole , B) 2.2 * 10^23  atoms

Question 2: A) 0.283 mole , B) 0.283 mole , C) 1.7 * 10^23  atoms

Question 3: A) 0.016 mole ; B) C: 0.192 mole, H: 0.352 mole, O: 0.176 mole; C) C: 1.16 * 10^23  atoms, H: 2.12 * 10^23 atoms, O: 1.06 * 10^23 atoms

Explanation:

Question 1

A) Number of moles are calculated with the following formula:

number of moles = Mass / Molecular weight

mass of gold = 72.04 g

Molecular weight of gold = 197 g/mole

number of moles of gold = 72.04 / 197 = 0.365 mole

B) To calculate the number of atoms, the Avogadro number is needed, as follows :

Number of atoms = moles * Avogadro number

Avogadro number = 6.023 * 10^23 atoms/mole

Number of atoms of gold = 0.365 * 6.023 * 10^23 = 2.2 * 10^23  atoms

Question 2

A) Following the same procedure as before

mass of NaCl = 16.55 g

Molecular weight of NaCl = 35.5 + 23 = 58.5 g/mole

number of moles of NaCl  = 16.55 / 58.5 = 0.283 mole

B) Each molecule of NaCl has 1 atom of Na and 1 atom of Cl, that means each mole of NaCl has 1 mole of Na and 1 mole of Cl, so:

number of moles of Na = 0.283 mole

number of moles of Cl = 0.283 mole

C) Following the same procedure as before

Number of atoms of sodium = Number of atoms of chlorine =  0.283 * 6.023 * 10^23 = 1.7 * 10^23  atoms

Question 3

A) Following the same procedure as before

mass of sucrose = 5.432 g

Molecular weight of sucrose = 342.3 g/mole

number of moles of sucrose = 5.432 / 342.3 = 0.016 mole

B) Each molecule of C12H22O11 has 12 atoms of C, 22 atoms of H and 11 atoms of O, that means each mole of C12H22O11 has 12 moles of C, 22 moles of H and 11 moles of O, so:

moles of C = 12*0.016 = 0.192 mole

moles of H = 22*0.016 = 0.352 mole

moles of O = 11*0.016 = 0.176 mole

C) Following the same procedure as before

Number of atoms of C = 0.192 * 6.023 * 10^23 = 1.16 * 10^23  atoms

Number of atoms of H = 0.352 * 6.023 * 10^23 = 2.12 * 10^23  atoms

Number of atoms of O = 0.176 * 6.023 * 10^23 = 1.06 * 10^23  atoms

chemistry sucks a**

explanation:

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.