Atomic Mass of Noodlium

Name: ______Date: ______

Materials and Equipment • Triple beam balance • A Sample of Noodlium

Procedure 1. Obtain a sample of “noodlium” from your teacher. It contains a mixture of different isotopes, i.e. pasta noodle varieties. 2. Measure and record the total mass of the sample in the baggie ______g total mass of sample 3. Carefully empty the contents onto a large flat surface. Measure the mass of the empty baggie: ______g mass of the baggie What is the mass of the sample alone? ______g sample mass 4. Sort and record the “pasta noodles” by type. Count the total number of noodles. 5. Find the average mass of each type of “pasta noodle”. Determine the average by measuring the mass of 10 noodles of each type and dividing by 10.

Type of noodle Average mass (g) (a) ______

(b) ______

(c) ______

(d) ______

6. Calculate the percentage of each noodle type (isotope) in the sample, using the formula: % abundance = # of noodles of a given type x 100% Total Number of Noodles Name: ______Date: ______

Type of Noodle % abundance (a) ______

(b) ______

(c) ______

(d) ______

7. Determine the weighted average atomic mass for noodlium using the formula:

{ [massa x (%)a] + [ massb x (%)b] + [massc x (%)c] + [ massdx (%)d] } ÷ 100

Weighted average mass of our sample of noodlium is: ______g Questions 1. Is your weighted average mass consistent with the total sample mass? 2. Define isotope. Explain the differences between neon-19, neon-20, and neon-22. 3. Using the data provided, find the Atomic Masses of the following elements: a. b.

Isotope Atomic Mass Percent Isotope Atomic Percent Abundance Mass Abundance H - 1 1.008amu 99.985% Cl – 35 35.01amu 75.8% H – 2 2.014amu 0.015% Cl – 37 37.013amu 24.2% H – 3 3.016amu Neglect

c. d. Isotope Atomic Percent Isotope Atomic Percent Mass Abundance Mass Abundance Mg -24 23.98amu 78.60% Li - 6 6.015amu 7.68% Mg- 25 24.99amu 10.11% Li – 7 7.016amu 92.32% Mg- 26 25.98amu 11.29%

e. Isotope Atomic Percent Mass Abundance Pb – 206 205.98amu x Pb - 207 206.98amu x Pb - 208 207.98amu 100-2x