How many atoms are there in a 591 g sample of gold (Au)?
Initial calculation:
Calculation in Sigfigs:
C.4.4 Apply the mole concept to determine the mass, moles, number of particles, or volume of a gas at STP, in any given sample, for an element or compound.
Learning Goal:
I can use the mole concept to determine the mass, moles, and number of particles in any sample.
Need - paper, pencil, and a scientific calculator
Recommended Free Calculators - natural scientific calculator or Demos
C.4.4 Apply the mole concept to determine the mass, moles, number of particles, or volume of a gas at STP, in any given sample, for an element or compound.
Learning Goal:
I can use the mole concept to determine the mass, moles, and number of particles in any sample.
Need - paper, pencil, and a scientific calculator
Recommended Free Calculators - natural scientific calculator or Demos
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).
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.
Match the number of significant figures to each expression:
| Draggable item | arrow_right_alt | Corresponding Item |
|---|---|---|
1000 | arrow_right_alt | Four significant figures |
0.02030 | arrow_right_alt | Three significant figures |
2.00 | arrow_right_alt | One significant figure |
How many atoms are there in a 591 g sample of gold (Au)?
Initial calculation:
Calculation in Sigfigs:
How many atoms are in 4.000 grams of carbon (C)?
Initial calculation:
Calculation in Sigfigs:
How many grams are in 6.80 x 1012 atoms of carbon (C)?
Initial calculation:
Calculation in Sigfigs:
How many grams are in 10.5 x 1031 atoms of sulfur (S)?
Initial calculation:
Calculation in Sigfigs:
How many grams are in 7.00 x 1021 atoms of aluminum (Al)?
Initial calculation:
Calculation in Sigfigs:
How many atoms are there in 0.802 g Hg?
Initial calculation:
Calculation in Sigfigs:
What is the molar mass of C2H8?
How many molecules of C2H8 are there in 4.01x105 g C2H8?
Hint - you calculated the molar mass in question 8.
Initial calculation:
Calculation in Sigfigs:
What is the mass (in grams) of 9.52 x 106 molecules of C2H8?
Initial calculation:
Calculation in Sigfigs:
