9. Give the number of protons, neutrons, and electrons in an atom of the \"Sr is
ID: 999569 • Letter: 9
Question
9. Give the number of protons, neutrons, and electrons in an atom of the "Sr isotope. a, 52 p, 38 n. 52 e d. 38 p, 52 n, 38 e b, 38 p, 90 n, 38 e c, 38 p, 38 n, 38 e e, 90 p, 38 n, 90 e 10. Calculate the molarity of a solution that contains 70.0 g ofHaso, in 280. ml. ofsolution. d. 9.78 M b, 2.55 M e, 11.84 M c, 8.62 M 11. Isotopes are atoms of the same element that a. have different nuclear charges. b, have different numbers of protons. d, have different numbers of electrons e, have different numbers of Deutrons. c. have different atomic numbers. 12. How many grams of KoH are contained in 400, mLofo.250 MKOH solution? a. 89.8 g. d, 35.1 g b, 8.98 g e, 5.61 g e, 12.4 g 13. Simple positively charged ions are always than the neutral atoms from which they are formed. d. smaller b, larger c, the same size 14. The number of can change without changing the element. d, all of the above e. neutrons and electrons only protons only 15. is a noble gas. 16. The number of electrons in a neutral atom of an element is always equal to the of the element. b- isotope number e, atomic mass unit 17. A 10.0-L nask contains o 400 mole ofH,.0300 mole ofHe and 0.500 mole of Ne at 350c. What is the partial pressure of the Ne? 1.26 atm b, 0.144 atm e. 3.03 atm c. 1.69 atmExplanation / Answer
Ans:
9) d (38p, 52n , 38e)
10) b
convert grams of H2SO4 into moles by dividing by its molar mass. The molar mass of H2SO4 is 98.0785.
n = 70/98.0785 = 0.7137 moles
also given,0.28 L
therefore: M = mol/L = .7137/.28 = = 2.548
11) e
have the same number of protons and electrons, but different number of neutrons
12) e (5.61grams)
MW = 56.104g/mol ;
for 1 molar, 56.104 grams in liter
therefore, 0.25M = 14.026 g/L
14.026g/L x 1 L/1000ml x 400 ml = 5.61 grams
13) d (positively charged are smaller)
14) b
15) a
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