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CHM2045: Worksheet 1 ch 1 and 2 (Harris) Name: Ywonne, le Grad TAs name and e-mail address: Undergrad TAs name You must show your work to display to your TA that you have completed each question. 1. What is the answer to the following calculation in scientific notation: 3.58 +4.54+5.2 + 8.627? A) 2.0947x10! ¥ 12 ) 1 7. B) 2.095x101% 1232 20.947 .09x101 Dy 2.1x10!* 2 aq Ras ve E) 2x10! X t % DR: 2. What is the answer to the following calculation: 71.262+4.5 -6%10! _ (5.7629 1G 5.24 _ — = S24 3. An unknown substance has a density of 0.983 g/cm3. What is this density in ng/jum3? A) 98.3 B) 0.983 183 1000000000 n 3 C) 9.83x107 WA & foe’merrent x _| em ()9.83x10~ 1 em*® | ]50000000000 pos E) 9.83x10 4 4. Which one of the following has the largest numerical value? A) atomic number of *°Ca2.6 B) number of neutrons in SMn 30 number of neutrons in ®cr 3 D) atomic number of 73Na !\ E) mass number of 4Mg 74.31 5. Elemental magnesium consists of three isotopes: *4Mg with an accurate mass of 23.99 amu, Mg with an accurate mass of 24.99 amu, and 76Mg with an accurate mass of 25.99 amu. If *4Mg is 79% of naturally occurring magnesium, what is the percent abundance of 7°Mg? Gr 23.24(0.79) + 24.94 (0-U-x) + 2s.a4( xX j= 24-3) jie (ASD + SDH DUA ZS.A4 x = 243) E) 21% xX =ONWN 6. What is the symbol for a species composed of 38 protons, 52 neutrons, and 36 electrons? A) Kx 90Sy 2+ ) Sr % D) 2Kr« 
