# The mass fraction of impurities in limestone is 6.25%. Calculate the mass of the basic substance (calcium carbonate)

The mass fraction of impurities in limestone is 6.25%. Calculate the mass of the basic substance (calcium carbonate) contained in 1.5 tons of natural limestone. Given: ω (impurities) = 6.25%, m (sample) = 1.5 tons.
Find: ω (basic substance) -?
Decision.
1. Let’s calculate the mass of impurities in a sample of natural limestone:
m (impurities) = (ω (impurities) • m (sample)): 100% = 6.25% • 1.5 t: 100% = 0.09375 t.
2. Calculate the mass of the main substance:
m (basic substance) = m (sample) – m (impurities) = 1.5 t – 0.09375 g = 1.40625 t.
2. Let’s calculate the mass fraction of the main substance:
ω (basic substance) = m (basic substance) / m (sample) = 1.40625: 1.5 = 0.9375, or,
multiplying this number by 100%, we get 93.75%. Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.