Page 488 - Chemistry eBook

thepHofasolu dronium ion co
creases by a fac reases by a fact creases by a fac reases by a fact
samples of the ith a different in ymol blue, bro ppear blue if the
-milliliter sampl y 40.0 milliliter
larity of the Na
M M
ion is spont en-3 nuclei, neously emitte rogen-2 nuclei
ble?
clei of H-1 and clei of H-1 and clei of H-2 and clei of H-1, H-
tion is centr
tor of or of tor of or of
same dicato cres
pH o
(3)
(4) 9.9
e of N s of 0
OH(a
(3) (4)
neou but
from . Whi
H-2, H-3, H-3, , and
What is the half-life of this radioisotope?
changed from 4 to 3, ation of the solution
10 10
100 100
solution are tested, r. All three indicators, ol green, and thymol
f the solution is 7.8
June 2013 #48
aOH(aq) is neutral- .50 M HCl. What is
q)?
0.25 M 0.50 M
(2) 9.6 h (4) 24 h
(1) 21H 􏰀 21H → 42He (2) 2H2 􏰀 O2 → 2H2O
(1) 236Ra 92
(2) 228Ra 88
(3) 236U 92
(4) 228U 88
Sample Regents Questions
48 Given the equation representing a nuclear reaction in which X represents a nuclide:
232Th → 4He 􏰀 X 90 2
Which nuclide is represented by X?
49 After decaying for 48 hours, _1_ of the original
6
mass of a radioisotope sample remains unchanged.
1
(1) 3.0 h
(3) 12 h
Answer: Choice #2
sly emitted from
radEiaxtpiolannatisionn:oWt eneedtobalancethisequationtofigureouttheanswer.
(3) 63Li 􏰀 10n → 31H 􏰀 42He
ch hIyndroorgdenr nfourcltehi e mass a(n4d) cChaaOrg􏰀e CtoObe→eCquaaClOon both sides, X has to have a
hydrogen-1 nuclei
Answer
50 Which balanced equation represents nuclear fusion?
23
mass of 228 and a charge of 228X. Now, which element is X? Check the atomic only 88
onlynumber/charge on Reffy, Periodic Table (p. 9). Ra’s atomic number is 88. only
H-3Therefore, it must be Ra!
c c
w hm
a
7 0
o
0 0
ta
g ad d
a
2
n
487 © UNIT 12: NUCLEAR CHEMISTRY