June 2005 Chemistry Regents #31-40
Highlight to reveal answers and explanations
Back to Regents Exams
|4||0+1e is a positron Table O|
|33 An electron in an atom moves from the ground state to
an excited state when the energy of the electron
(3) remains the same
|34 Which symbol represents a particle that has the same
total number of electrons as S2–?
(1) O2– (3) Se2–
(2) Si (4) Ar
|4||S2– has 16 + 2 more
electrons =18 total
same as Ar
|3||between 141 and 171|
|36 Which substance has a chemical formula with the same
ratio of metal ions to nonmetal ions as in potassium sulfide?
(1) sodium oxide
(2) sodium chloride
(3) magnesium oxide
(4) magnesium chloride
|1||same ratio would be elements from the same groups as the ones being replaced|
|37 The molecular formula of glucose is C6H12O6.
What is the empirical formula of glucose?
(1) CHO (3) C6H12O6
(2) CH2O (4) C12H24O12
|2||reduced = empirical|
|38 According to Reference Table F, which of these
compounds is the least soluble in water?
(1) K2CO3 (3) Ca3(PO4)2
(2) KC2H3O2 (4) Ca(NO3)2
|3||Phosphates are insoluble|
|39 A sample of a substance containing only magnesium and
chlorine was tested in the laboratory and was found to be composed of
74.5% chlorine by mass. If the total mass of the sample was 190.2 grams,
what was the mass of
(1) 24.3 g (3) 70.9 g
(2) 48.5 g (4) 142 g
|2||25.5% Mg x190.2g=48.5g Mg|
|3||Br-Br same element Zero electronegativity difference|
|Back to Regents Exams|