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Calculate the empirical for the molecular formula mass and the molar mass of each of the following minerals:

(a) Limestone, CaCO3
(b)halite, NaCl
(c)beryl, Be3Al2Si6O18
(d)malachite, Cu2(OH)2CO3
(e)turquoise, CuAl6(PO4)4(OH)8(H2O)4

User Shadi
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Final answer:

The empirical formula mass is the sum of the atomic masses in the empirical formula, while the molar mass is the mass of one mole of the compound. The empirical and molar masses of limestone, halite, beryl, malachite, and turquoise are calculated by adding up the atomic masses of the elements in their formulas. The empirical formula mass and molar mass depend on the elements present in the compound.

Step-by-step explanation:

The empirical formula mass of a compound is the sum of the atomic masses of all the atoms in the empirical formula. The molar mass, on the other hand, is the mass of one mole of the compound and is equal to the sum of the atomic masses of all the atoms in the molecular formula.

(a) Limestone, CaCO3:

The empirical formula mass is calculated by adding up the atomic masses of calcium (Ca), carbon (C), and three oxygen (O) atoms. The atomic mass of Ca is 40.08 g/mol, the atomic mass of C is 12.01 g/mol, and the atomic mass of O is 16.00 g/mol. Therefore, the empirical formula mass of CaCO3 is 40.08 + (12.01 + 3 * 16.00) = 100.09 g/mol.

The molar mass is equal to the empirical formula mass since the molecular formula of limestone is also CaCO3. Therefore, the molar mass of limestone is 100.09 g/mol.

(b) Halite, NaCl:

The empirical formula mass of halite is calculated by adding up the atomic masses of sodium (Na) and chlorine (Cl). The atomic mass of Na is 22.99 g/mol and the atomic mass of Cl is 35.45 g/mol. Therefore, the empirical formula mass of NaCl is 22.99 + 35.45 = 58.44 g/mol.

The molar mass is equal to the empirical formula mass since the molecular formula of halite is also NaCl. Therefore, the molar mass of halite is 58.44 g/mol.

(c) Beryl, Be3Al2Si6O18:

The empirical formula mass of beryl is calculated by adding up the atomic masses of beryllium (Be), aluminum (Al), silicon (Si), and oxygen (O). The atomic mass of Be is 9.01 g/mol, the atomic mass of Al is 26.98 g/mol, the atomic mass of Si is 28.09 g/mol, and the atomic mass of O is 16.00 g/mol. Therefore, the empirical formula mass of Be3Al2Si6O18 is 9.01 * 3 + 26.98 * 2 + 28.09 * 6 + 16.00 * 18 = 537.51 g/mol.

(d) Malachite, Cu2(OH)2CO3:

The empirical formula mass of malachite is calculated by adding up the atomic masses of copper (Cu), oxygen (O), and carbon (C). The atomic mass of Cu is 63.55 g/mol, the atomic mass of O is 16.00 g/mol, and the atomic mass of C is 12.01 g/mol. Therefore, the empirical formula mass of Cu2(OH)2CO3 is 63.55 * 2 + 16.00 * 2 + 12.01 * 1 + 16.00 * 3 = 221.15 g/mol.

The molar mass is equal to the empirical formula mass since the molecular formula of malachite is also Cu2(OH)2CO3. Therefore, the molar mass of malachite is 221.15 g/mol.

(e) Turquoise, CuAl6(PO4)4(OH)8(H2O)4:

The empirical formula mass of turquoise is calculated by adding up the atomic masses of copper (Cu), aluminum (Al), phosphorus (P), oxygen (O), and hydrogen (H). The atomic mass of Cu is 63.55 g/mol, the atomic mass of Al is 26.98 g/mol, the atomic mass of P is 30.97 g/mol, the atomic mass of O is 16.00 g/mol, and the atomic mass of H is 1.01 g/mol. Therefore, the empirical formula mass of CuAl6(PO4)4(OH)8(H2O)4 is 63.55 + 26.98 * 6 + 30.97 * 4 + 16.00 * 23 + 1.01 * 8 = 1027.23 g/mol.

The molar mass is equal to the empirical formula mass since the molecular formula of turquoise is also CuAl6(PO4)4(OH)8(H2O)4. Therefore, the molar mass of turquoise is 1027.23 g/mol.

User Julien Greard
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Step-by-step explanation:

Molar mass

The mass present in one mole of a specific species .

The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .

(a) Limestone, CaCO₃

Molar mass of the atoms are -

Calcium , Ca = 40 g / mol

Carbon , C = 12 g/mol

Oxygen , O = 16 g/mol

Molecular mass of CaCO₃ = (40 g / mol ) + ( 12 g/mol ) + ( 3 * 16 g/mol ) = 100 g/mol.

(b) halite, NaCl

Molar mass of the atoms are -

Sodium , Na = 23 g/mol

Chlorine , Cl = 35.5

Molecular mass of NaCl = 23 + 35.5 = 58.5 g/mol .

(c) beryl, Be₃Al₂Si₆O₁₈

Molar mass of the atoms are -

Beryllium , Be = 9 g/mol

Aluminum , Al = 27 g/mol

Silicon , Si = 28 g/mol

Oxygen , O = 16 g/mol

Molecular mass of Be₃Al₂Si₆O₁₈ = ( 3* 9 ) + ( 2*27 ) + ( 6 * 28 ) + ( 18 * 16 ) = 537 g/mol .

(d) malachite, Cu₂(OH)₂CO₃

Molar mass of the atoms are -

Copper , Cu = 63.5 g/mol

Oxygen , O = 16 g/mol

Carbon , C = 12 g/mol

hydrogen , H = 1 g /mol

Molecular mass of Cu₂(OH)₂CO₃ = ( 2 * 63.5 ) + ( 5 * 16 ) + ( 2 * 1 ) + ( 1* 12 ) = 221 g/mol.

(e) turquoise, CuAl₆(PO₄)₄(OH)₈(H₂O)₄

Copper , Cu = 63.5 g/mol

Aluminum , Al = 27 g/mol

Phosphorous , P = 31 g/mol

Oxygen , O = 16 g/mol

hydrogen , H = 1 g /mol

Molecular mass of CuAl₆(PO₄)₄(OH)₈(H₂O)₄ =

( 63.5*1) + (6 *27) + (4* 31 ) + (28 *16 ) + ( 16 *1 ) = 813 g/mol.

User Ralphilius
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