isotope project assignment, Lab Reports of Science education

Download isotope project assignment and more Lab Reports Science education in PDF only on Docsity! Beanium Isotope Lab Introduction & Purpose: What is an isotope? What does it mean to say that the atoms in a sample of an element are isotopes of each other? Ordinary beans are a lot bigger than atoms, but perhaps they can give you one or two clues about isotopes. We have talked in class about isotopes: atoms of the same element that differ in mass. For example, there are actually three different kinds of hydrogen atoms. Refer to the table below for the different kinds (or isotopes) of two common atoms. ISOTOPE PROTONS ELECTRONS NEUTRONS SIGNIFICANCE Protium 1 1 0 “normal” hydrogen Deuterium 1 1 1 “heavy hydrogen” Tritium 1 1 2 radioactive hydrogen Carbon-12 6 6 6 “normal” carbon Carbon-14 6 6 8 carbon-14 dating This lab exercise is designed to show you isotopes of an element in a simulation form. You will be asked to gather data about the “isotopes” and organize the data. If atoms were as large as beans they could be sorted, counted, and massed. In this experiment we will sort, count, and mass three different kinds of beans and imagine that we are observing three different isotopes of the same element (let’s call it BEANIUM). The three different isotopes are blackium, brownium, greenium and whitium. Finally we will calculate the isotopic mass, the isotopic abundance, and the atomic mass of the bean element. These experiments and calculations are equivalent to the way scientists actually determine the atomic mass of elements. As in real elements, the mixture of isotopes are collections of atoms of the element each having different masses because they have different numbers of neutrons. Unlike real isotopes, the individual isotopic particles of Beanium differ slightly in mass, so you will determine the average mass of each type of isotopic particle. Then you can calculate the "weighted average atomic mass" of Beanium. Definitions/ reference:  Isotopic mass – the average mass of the atoms of a specific isotope of an element  Isotopic abundance – what percent of the element’s atoms are a specific isotope  Atomic mass – the average mass of an element’s atoms #Protons: determine which element an atom is – determines the atomic number # electrons: determine the charge on an atom Protons = electrons – atom is neutral Protons> electrons – atom is positively charged (lost electrons) Protons< electrons - atom is negatively charged (gained electrons) # neutrons – determines the atomic mass of an atom. Determines the isotope number of the atom. Isotope: an atom of an element with a certain number of neutrons. Beanium Lab 1 NOTE: All atoms of an element are isotopes of that element. Most elements have 1, 2 or 3 naturally occurring isotopes. This means that in any sample of the element these naturally occurring isotopes are all present typically always in the same % ratio. For example: The element carbon has three isotopes: = 6 neutrons and is called Carbon -12 isotope 90% abundance = 7 neutrons and is called carbon-13 isotope 9% abundance = 8 neutrons and is called carbon-14 isotope 1% abundance % abundance means that in a sample of carbon (like a lump of coal or a diamond) 90% of the carbon atoms will be carbon-12, 9% will be carbon-13 and 1% will be carbon-14. Since not all the atoms in a sample of an element have the same mass, we have to calculate an average atomic mass for the element. The average atomic mass is calculated taking into account the different percents of each isotope present. Materials: Plastic cup or ziplock bags of beans (black, brown, & white); electronic balance Procedure: 1. Obtain a plastic cup which contains many atoms (beans) of BEANIUM. 2. Sort the atoms (beans) into a group for each isotope: black, brown, white. Record the total number of atoms and the number of each type of isotope (blackium, brownium, greenium and whitium) in the data table. 3. Determine the isotopic mass: a) find the total mass of each of the three isotope groups and record on data table b) find the average mass of a single atom of each isotope and record on the data table to the nearest 0.001g. EXAMPLE: I counted 340 white beans. They have a mass of 80 grams. The average mass of one white bean is 80 / 340 = 0.235 grams. 4. Find the isotopic abundance (% of beans) for each isotope by dividing the number of atoms of one isotope by the total number of atoms (black, brown, plus white) and multiplying by 100%. Record on the data table to the nearest 0.1%. EXAMPLE: There are a total of 500 atoms. 340 are white beans. Therefore, (340 ÷ 500) x 100% = 68.0% are white beans (whitium). Beanium Lab 2