The answer is: C. 0.00427 m.
A) 1 km = 1000000 mm.
d = 0.0000427 km · 1000000 mm/km.
d = 47.7 mm.
B) 1 hm = 100000 mm.
d = 0.000427 hm · 100000 mm/hm.
d = 42.7 mm.
C) 1 m = 1000 mm.
d = 0.00427 m · 1000 mm/m.
d = 4.27 mm.
D) 1 cm = 10 mm.
d = 4.27 cm · 10 mm/cm.
d = 42.7 mm.
Millimeter (abbreviated: mm, a thousandth part of metar) is an unit of distance in the metric system.
This is a case of metric system of measurements. The scale of the metric system only differs by a factor of 10. The scale (from greatest to least) is kiloliter, hectoliter, dekaliter, liter, deciliter, centiliter and milliliter. If the unit is 150 dL, and you want to find the equivalent dkL measurement, just move the decimal point 2 decimals places to the left (just follow the scale). The same procedure is done for the other metric units.
150 dL = 1.5 dkL
150 dL = 15 L
150 dL = 1,500 cL
150 dL = 15,000 mL
From the choices, the answer is letter C.
Answer:
% purity of limestone = 96.53%
Explanation:
Question (4).
Weight of impure CaCO₃ = 25.9 g
Molecular weight of CaCO₃ = 40 + 12 + 3(16)
= 100 g per mole
We know at S.T.P. number of moles of CO₂ = 1 and volume = 22.4 liters
From the given reaction, 1 mole of CaCO₃ reacts with 1 mole or 22.4 liters of
CO₂.
∵ 22.4 liters of CO₂ was produced from CaCO3 = 100 g
∴ 1 liter of CO₂ will be produced by CaCO₃ = 
∴ 5.6 liters of CO₂ will be produced by CaCO₃ = 
= 25 g
Therefore, % purity of CaCO₃ = 
= 
= 96.53 %
Professor of Physics Carlo Rubbia
