Which can act as both an oxidizing agent and a reducing agent? (A) H_2O_2 (B) Na
ID: 999353 • Letter: W
Question
Which can act as both an oxidizing agent and a reducing agent? (A) H_2O_2 (B) NaH (C) Na_2O (D) O_3 Which is the strongest reducing agent? (A) Ce (B) Li (C) Li^+ (D) Ce^3- 64. which type of radiation can be blocked by a thin piece of paper (A) I only (B) II only (C) III only (D) I and II 65. A 40.0 gram sample of^235U undergoes decay with a half-life of 7.0times10^3 years. what mass in grams of^235U remains after 2.1times10^9 years? (A) 13. (B) 10. (C) 5.0 (D) 1.4times10^-8 66. Identify the missing reactant in the synthesis of seaborgium, Sg. (A) 24998Cf (B) 24698 Cf (C) 24598Cf (D) 249102No 67. You just spilled 3 mL of concentrated sulfuric acid on your arm. what should you do first? (A) cover with a thick cloth (B) cover with solid NaHCO_3 (C) rinse with 6 M NaOH solution (D) rinse with copious amounts of water 68. which laboratory waste can be discarded down the drain? (A) I only (B) III only (C) II and III only (D) none of the chemicals listed 69. which will have the least vigorous reaction with water? (A) Na (B) Mg (C) K (D) Ca 70. How do the melting points change with increasing atomic number for the diatomic elements in Group 17? (A) decrease (B) increase (C) not predictable (D) little or no changeExplanation / Answer
63.
b) Li+, because it has the highest elecyrode potential for gaining an electron.
64.
only alpha radiations can be blocked. So option a) is correct.
65.
no- of half lives = 2.1*10^9/7*10^8 = 3
ending amount= beginning amount/2n
where n= no. of half lives=3
plugging in the values, we get amount left= 5 gram option c)
66.
atomic number of missing element= 106-8 = 98
atomuc mass= 263+4-18= 249.
so option (a) is correct.
67.
b), to neutralise the effect of H2SO4, note that NaOH is not used because it would be an acid-base reaction and large amount of heat would be released.
68.
B) three only, because ammonia and sulphuric acid are hazardous waste.
69.
D) Ca
70.
B) increase.