07-02_task2 (1)

1. Marie Curie was a Polish scientist that specialized in chemistry and physics. She wanted to understand how X-rays worked and noticed in her studies that the element, Uranium, gave off rays that could be measured but did not know what the rays were. She assumed that the rays came from the uranium itself instead of through different molecules interacting with each other. To study the rays, she used an instrument, called an electrometer, that studied the electricity that the rays passed through the air. Through this she was able to discover that the more uranium atoms there were in a compound, the stronger the rays that came off of it. She used this discovery to test other minerals that emitted more rays than Uranium, and discovered the elements Thorium, Polonium and Radium. Through her discoveries of these elements, scientists were able to find the structure of the atom and even how the rays can be used to fight cancer. What was Marie Curie’s observation? 2. What was Marie Curie's…

What you need is in the picture the chart is in there two but you might have to zoom in to see it Thank You

12. Four students were asked to complete a table for a science assignment. Each student selected one chemical element from each of four groups in the periodic table and then classified each element as a metal, a nonmetal, or a metalloid. Information About Which table was completed correctly? Some Chemical Elements Group Symbol Classification 10 Ni Nonmetal 14 Metalloid 2 Mg Metal 6 Pb Metal Information About Some Chemical Elements Group Symbol Classification 17 Nonmetal Ca Metal Rb Metal 15 As Metalloid Information About Some Chemical Elements Group Symbol Classification 13 B Metalloid 15 Metal 2 Ra Nonmetal 18 Не Metal Information About Some Chemical Elements Group Symbol Classification 11 Cu Metal 15 Sb Metal 16 Metalloid 2 Ne Nonmetal

Assuming that the shape of atoms is spherical, what is the diameter (in angstroms) of an atom that has a volume of 1.3 x 10 23 cm2? Note: Don't use significant figures in this question. Select one: OA. 3.475 OB. 1.737 Ti OC. 1.091 OD. 1.459 OE. 2.917 NEXT PAGE S PAGE

Row 2: Your answer is incorrect. olo There are only two naturally-occuring stable isotopes of boron, the masses of which are listed in the table below. Use whatever data you need from the ALEKS Periodic Table to calculate the natural abundance of each isotope and complete the table. 10. 11 Ar Round your entry for "B to 3 significant digits and your entry for "B to 3 significant digits. mass natural isotope x10 (amu) abundance 10B % 10.013 11.009

More than 40% of the world's population has limited access to clean water. One proposed method for the production of clean water involves removing salt from seawater. Which technique would be used to separate the salt from the salt water mixture?     a)   chromatography     b)   fractional distillation   c)     filtration     d)   simple distillation

00 %23 3. alt b. C. %3D d 7. 9. 5. 4 %24 2. # permitted the direct measurement of electrostatic field until the beam hit the screen exactly where it had been hitting before the fields were applied. This experiment Experiments were carried out in which a beam of cathode rays was first bent by a magnetic field and then bent back by an

Using scanning tunneling microscopy, scientists at IBM wrote the initials of their company with 35 individual xenon atoms. Part A 131.29 amu) Calculate the total mass of these letters in grams (mXe Express your answer using four significant figures. ΑΣφ ? |2.180 10-22 m = Previous Answers Request Answer Submit

Chemistry of Mars NASA's 1997 mission to Mars included a small robot, the Sojourner, that analyzed the composition of Martian rocks. Magnesium oxide from a boulder dubbed "Barnacle Bill" was analyzed and found to have the following isotopic composition: Mass (u) Natural Abundance (%) 39.9872 78.70 40.9886 10.13 41.9846 11.17 If essentially all of the oxygen in the Martian MgO sample is oxygen-16 (which has a mass of 15.9948 u), is the average atomic mass of magnesium on Mars the same as on Earth (24.31 u)?

12. The mass and % abundance for the four isotopes of chromium is given in the table below. Isotope Atomic Mass (u) % Abundance Cr-50 49.95 4.35 Cr-52 51.94 83.79 Cr-53 52.94 9.50 Cr-54 53.94 2.36 Calculate the average atomic mass of chromium. (Show your work.)

Use the mass spectrum 100% of mercury shown here to estimate the atomic mass of mercury. Esti- mate the masses and percent intensity val- ues from the graph to three significant figures. 30%- 196 198 199 200 201 202 204 Mass (amu) Intensity %

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Why must atomic masses be weighted averages rather than conventional average values?

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Referring to the posted calibration curve (image attached) ...A 2.345 g sample of a ruthenium ore was dissolved and diluted to 100.00 mL. 4.000 mL of this sample was removed, treated appropriately, and diluted to 50.00 mL. This solution has an absorbance of 0.320. Calculate how many grams of ruthenium (MW = 101.07 g/mol) were in the sample.Select one:1.6 1.3 51 52 1.2

Use the mass spectrum of lead shown here to estimate 100% - the atomic mass of lead. Esti- mate the mass and percent in- tensity values from the graph to three significant figures. 50%- 204 206 207 208 Mass (amu) Intensity %

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