Chemistry

2019 U.S. National Chemistry Olympiad Local Section Exam Question 11

The concentration of sulfate ion in a solution is measured by precipitating the sulfate as BaSO4, filtering the precipitate on ashless filter paper, and heating the filter paper and precipitate in a tared crucible with a Bunsen burner. Which error will result in a sulfate concentration that is higher than the actual concentration?

(A) The empty crucible contains a few drops of water when it is tared.
(B) A glass fiber filter is used instead of ashless filter paper.
(C) Some fine precipitate is not captured by the filter.
(D) Some of the sulfate-containing solution spills before the BaCl2 solution is added.
Math

Barton College Practice Placement Test Question 47

The temperature, in degrees Fahrenheit, over a twelve hour period is given by the function T(t) = ‐0.5t2 + 6t + 30, where t = 0 denotes 6:00 a.m. When is the morning temperature 47.5o F?

(A) 12 noon
(B) 11:00 a.m.
(C) 10 a.m.
(D) 9:00 a.m.
English

I have always admired Seymour’s ______; I’ve never seen him rattled by anything.

a. aplomb
b. confluence
c. propriety
d. compunction
e. nostalgia
English

__________ our low annual fee, you will receive a 20% discount if you sign up this week.

a. Because
b. While
c. In spite of
d. In addition to
English

Created in October, 1972, the Consumer Product Safety Commission, which enacted a host of regulations affecting a wide range of goods, from overly flammable attresses to unhealthy aerosol sprays to fireworks.

(A) the Consumer Product Safety Commission, which enacted a host of regulations affecting a wide range of goods
(B) the Consumer Product Safety Commission enacted a host of regulations affecting a wide range of goods
(C) a host of regulations affecting a wide range of goods enacted by the Consumer Product Safety Commission
(D) a host of regulations enacted by the Consumer Product Safety Commission, which affected a wide range of goods
(E) when a host of regulations affecting a wide range of goods was enacted by the Consumer Product Safety Commission
English

Despite years of poverty and ——-, the poet Ruth Pitter produced work that is now ——- by a range of literary critics.

(A) security . . hailed
(B) depression . . criticized
(C) celebrity . . publicized
(D) inactivity . . undermined
(E) adversity . . acclaimed
English

Choose the sentence that is NOT correctly written or that is unclear. If all sentences are correct, choose answer d.

a. His jacket is just like mine.
b. Talia went to yoga class, and that she forgot her mat.
c. Indira visits her relatives frequently.
d. No mistakes.
United States History

“Slavery now stands erect, clanking its chains on the territory of Kansas, surrounded by a code of death, and trampling upon all cherished liberties.” This statement was most likely made by a(n)

(A) Whig
(B) muckraker
(C) plantation owner
(D) Democrat
(E) abolitionist
English

Choose the sentence that is NOT correctly written or that is unclear. If all sentences are correct, choose answer d.

a. The free passes were given to Lena and me.
b. Where’s my purple umbrella?
c. After midnight, the light on the front porch goes off.
d. No mistakes.