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Copy of Two-Step Molar Conversion 2 (5/28/2026)
By Jason Poe
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Last updated 20 days ago
12 questions
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Significant Figures (Sigfigs)
SigFig Rules
:
All non-zero digits are significant (211.8 has four sigfigs).
Zeros between non-zero digits are significant (20007 has five sigfigs).
Leading zeros in a number are not significant (0.0085 has two sigfigs).
Trailing zeros are not significant unless there is a decimal in the number (0.0050 has two sigfigs; 4100.0 has five sigfigs).
Trailing zeros in a whole number without a decimal are not significant (1000 has one SigFig).
For conversions
- use the same number of sigfigs as the original value.
Rounding after solving a problem
:
If the original number was 2.140 x 107
Four sigfigs (2.140); therefore, the answer must also have four sigfigs.
If the product was 1.150672 x 105, then it would need to be rounded to 1.151 x 105.
Examples
:
0.00456 - 3 sigfigs
2000 - 1 sigfig
1.20 × 10² - 3 sigfigs
150.0 - 4 sigfigs
Question 1
1.
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Corresponding Item
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Question 2
2.
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Corresponding Item
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Question 3
3.
How many molecules are in
2.50 moles of NaCl?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 4
4.
How many grams of CO
2
are in 0.100 moles of it?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 5
5.
How many molecules of H
2
O are in 5.00 moles of it?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 6
6.
How many grams are in 3.00 moles of C
6
H
12
O
6
?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 7
7.
How many molecules are in 0.250 moles of KCl?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 8
8.
How many molecules are in 50.0 grams of NaCl?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 9
9.
How many molecules are in 10.0 g of CO
2
?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 10
10.
How many molecules are in 25.0 g of H
2
O?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 11
11.
How many molecules are in 100.0 g of C
6
H
12
O
6
?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Question 12
12.
How many grams are in 5.00 x 10
24
molecules of KCl?
Initial calculation (not rounded): _______
Calculation rounded using sigfigs: _______
Match the correct number of significant figures to each value.
1.20 x 10
3
4
0.00456
3
100.0
3
How many significant figures will the answer to each have?
5.678 + 2.4
4
12.22 - 0.002
3
3.00 x 4.5
3