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The molecular mass of water (H₂O) is 18 u. How many protons are there in 1.0 L of liquid water?
20. Heat and Temperature
Moles and Avogadro's Number
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How many moles are in a block of lead?
A
24
B
42
C
56
D
75
E
89
F
34
Verified step by step guidance1
First, identify the molar mass of lead (Pb). The molar mass of lead is approximately 207.2 grams per mole.
Convert the mass of the lead block from kilograms to grams. Since 1 kilogram equals 1000 grams, multiply 7.0 kg by 1000 to get the mass in grams.
Use the formula to calculate the number of moles: \( \text{moles} = \frac{\text{mass in grams}}{\text{molar mass}} \).
Substitute the mass of the lead block in grams and the molar mass of lead into the formula.
Perform the division to find the number of moles of lead in the block.
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