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1. A chromoly (a 41xx series steel) steel ball bearing weighs 4.516 grams. It co

ID: 883994 • Letter: 1

Question


1. A chromoly (a 41xx series steel) steel ball bearing weighs 4.516 grams. It contains the following components by weight 0.040% Sulfur 0.20% Silicon 0.035% Phosphorus 0.50% Manganese 0.30% Carbon 0.20% Molybdenum 0.95% Chromium 97.775% Iron Determine how many atoms are in the ball bearing. 2. Assume the alloy in problem 1 has an even distribution of all of the alloying elements. If we created a new ball bearing by removing 10 sextillion atoms from the original ball bearing (a) how much would fling chromium in the new ball bearing weigh? (b) how much would the new ball bearing

Explanation / Answer

mass of ball = 4.516 grams

amount of sulfur = 0.040%

mass of sulfur = 0.040/100 * 4.516

= 0.00180 grams

atoms of sulfur = 0.00180 / 32 * 6.023x1023

= 3.387x1019

amount of silicon = 0.20%

mass of silicon = 0.20/100 * 4.516

= 0.009032 grams

atoms of silicon = 0.009032 / 28.085 * 6.023x1023

= 1.936x1020

amount of phosphorous = 0.035%

mass of phosphorous = 0.035 / 100 * 4.516

= 0.00158 grams

atoms of phosphorous = 0.00158 / 30.97 * 6.023x1023

= 3.072x1019

amount of manganese = 0.50%

mass of manganese = 0.50 / 100 * 4.516

= 0.02258 grams

atoms of manganese = 0.02258 / 54.938 * 6.023x1023

= 2.475x1020

amount of carbon = 0.30%

mass of carbon = 0.30 / 100 * 4.516

=0.0135 grams

atoms of carbon = 0.0135 / 12 * 6.023x1023

= 6.775x1020

amount of molybdenum = 0.20%

mass of molybdenum = 0.20 / 100 * 4.516

= 0.009032 grams

atoms of molybdenum = 0.009032 / 95.94 * 6.023x1023

= 5.67x1019

amount of chromium = 0.95%

mass of chromium = 0.95 / 100 * 4.516

= 0.0429 grams

atoms of chromium = 0.0429 / 51.99 * 6.023x1023

= 4.969x1020  

amount of iron = 97.775%

mass of iron = 97.775 / 100 * 4.516

= 4.4155 grams

atoms of iron = 4.4155 / 55.845 * 6.023x1023

= 4.762x1022

Total number of atoms in ball bearing = 3.387x1019 + 1.936x1020 + 3.072x1019 + 2.475x1020 +  6.775x1020 + 5.67x1019 + 4.969x1020 + 4.762x1022

= 4.935x1022 atoms