Hardness is defined as calcium and magnesium ion content. Since most hardness is caused by carbonate mineral deposits and does not distinguish calcium and magnesium ions, hardness is usually reported as parts per million (ppm) of calcium carbonate (CaCO3, by weight). A water supply with a hardness of 100 ppm contains the equivalent of 100 g of CaCO3 in 1 million g of water or 0.1 g in 1 L of water (or 1000 g of water since the density of water is about 1 g/mL). For a water supply with a hardness 134 ppm, what is its hardness in mol/L?

Question

Hardness is defined as calcium and magnesium ion content. Since most  hardness  is  caused  by  carbonate  mineral deposits and does not distinguish calcium and magnesium ions,  hardness  is  usually  reported  as  parts  per  million  (ppm)  of  calcium  carbonate  (CaCO3, by weight).  A water supply with a hardness of 100 ppm contains the equivalent of 100 g of CaCO3 in 1 million g of water or 0.1 g in 1 L of water (or 1000 g of water since the density of water is about 1 g/mL). For a water supply with a hardness 134 ppm, what is its hardness in mol/L?

Dr. Neutron · Accepted Answer

1st: 100ppm= 0.1g/L or0.100g/L so 134ppm= 0.134g/L. 2nd:.134g/L divide by molar mass of CaCO3 which is 108.09g/mol. Gram and gram cancel out left you with mole and liter Answer: .00124 mol/L

evan · Answer

caco3 = 100.08g/mol