Like in a cat's eye, the human pupil changes shape in response to changes in
the environment. What is the most likely function of this structure?
A. To allow humans to read
B. To allow humans to see clearly in different levels of light
C. To allow humans to see shades in color
D. To allow humans to see at varying distances
Answer:
B.
Our pupils contract and expand depending on the amount of light at any given time in order to avoid being blinded and to see better in the darkness.
Quinine in a 1.664-g antimalarial tablet was dissolved in sufficient 0.10 M to give 500 mL of solution. A 15.00-mL aliquot was then diluted to 100.0 mL with the acid. The fluorescence intensity for the diluted sample at 347.5 nm provided a reading of 327 on an arbitrary scale. A standard 100 ppm quinine solution registered 180 when measured under conditions identical to those for the diluted sample. Calculate the mass of quinine in milligrams in the tablet.
Answer:
605.6mg of quinine
Explanation:
Based on Lambert-Beer's law, the intensity of an optical measurement is directely proportional to its concentration.
Unknown concentration gives a reading of 327
100 ppm gives 180 of intensity
The concentration of the diluted quinine tablet is:
327 * (100ppm / 180) = 181.67 ppm. The final dilution
The concentration of the first diluted solution is:
181.67 ppm * (100.0mL / 15mL) = 1211ppm
ppm could be defined as mass of solute (In this case of quinine) in mg per liter of solution. That is:
1211mg / L
As the tablet was diluted to 500mL = 0.5L, the mass of the quinine is:
0.5L * (1211mg / L) =
605.6mg of quinineWhich of these actions is an example of erosion caused by gravity?
A.
Constant freezing and thawing water forming a hole in an asphalt road
B.
Pieces of rock breaking off and falling from a mountain top
C.
Chemicals in the air dissolve minerals in a marble statue
D.
Plant roots widening cracks in a large granite rock
Answer:
The answer is a
Explanation:because yes
Answer: The answer is B.
Explanation: The rocks falling off is caused by gravity. Other options don't include effects of gravity; Therefore, B is correct.
An unknown compound was found to be soluble in concentrated sulfuric acid; however, the 2,4-DNP, chromic acid, and potassium permanganate gave negative results. The only positive result detected was the ferrous hydroxide test. What is the most likely functional group present in such compound
Explanation:
2,4-DNP is negative: aldehyde and ketone absent
Chromic acid is negative: alcohol absent.
KMnO4 test negative: alkene absent
The only positive result is for Fe(OH)2.
Nitro group-containing compounds react with ferrous hydroxide to give amine and ferric hydroxide red ppt. Hence given compound contains the nitro group (-NO2).
Help please I’ll mark as brainiliest
Answer:
B B
W BW BW
W BW BW
Explanation:
Hope this helps
Today, there are ____ GMO crops currently produced in the US.
A. 120
B. 10
C. 55
D. 1000
Answer: I think that is 55
Explanation: I hope I help
Please help with this one
Answer:
15g
Explanation:
hope this helped
the sum of two number is 50,and their difference is 30.find the sum
Answer:
40 and 10
Explanation:
40 plus 10 is 50 40 minus 10 is 30
Answer:
40 and 10
Explanation:
5. What physical property of foam makes it a good choice to
use in life vests?
A. Foam has a relative density less than water.
B. Foam is a good thermal insulator.
C Foam is non-magnetic.
D. Foam is soluble in water.
Trojans are _____.
a. asteroids which fall to the Earth
b. long-period comets
c. planets with ring systems
d. asteroids affected by Jupiter's gravity
Answer:
d. asteroids affected by Jupiter's gravity
Explanation:
A Trojan horse or Trojan is a type of malware that is often disguised as legitimate software. Trojans can be employed by cyber-thieves and hackers trying to gain access to users' systems. Users are typically tricked by some form of social engineering into loading and executing Trojans on their systems.
Answer:
D
Explanation:
D is the correct answer, they are planets that are close to the center star
What is the molar mass of AlCl3
Answer:
133.34 g/moles
Explanation:
but to make life easy it could be 133.4 g/ moles as well