Name
Date
Pd
General Chemistry – Unit 8 Activity
Counting Particles
1. Observe the beakers of corn and rice on the lab station. Make a guess of how
many kernels of corn and grains of rice are in the beakers. Record your guess.
Guessed number of corn kernels
__________
Guessed number of rice grains
__________
2. Determine the mass of 25 corn kernels and 25 rice grains.
Mass of 25 kernels
__________
Mass of 25 grains
__________
3. Based on the information in question #2, propose a method for estimating the
number of corn kernels and rice grains in their respective beakers. Write a
brief procedure for this, including plans for calculations, in the space below.
4. Carry out the procedure from question #3, showing all work below. If you need
any additional equipment, ask your instructor.
Estimated number of kernels of corn
__________
Estimated number of grains of rice
__________
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U8 gen Counting Particles
5. Count the actual number of kernels of corn in your beaker and record below.
Actual number of kernels of corn
__________
6. Compare the estimated value with the actual amount of corn and rice that was
in each beaker by using the percent error equation. Show your work below then
comment on the ability to accurately estimate the amount of large quantities of
very small objects.
7. Based on the data collected in this activity, how would the mass of 525 kernels
of corn compare to the mass of 525 grains of rice? Mathematically validate your
response.
8. How would the number of particles compare in 10.0 g of rice as compared to
10.0 g of corn? Mathematically validate your response.
9. In chemistry we deal with very small particles, far smaller than even a grain of
rice or kernel of corn. Write a conclusion for this activity relating the
techniques used to determine the number of grains in each beaker to how
chemists might determine the number of atoms in 42.5g of pure gold.
Modeling Chemistry
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U8 gen Counting Particles