A pound is approximately 0.45 kilogram. A person weighs 87 kilograms. What is the person’s weight, in pounds, when expressed to
the correct number of significant figures?
A. 190 lb
B. 180 lb
C. 52 lb
D. 39 lb
A. 190 lb
B. 180 lb
C. 52 lb
D. 39 lb
2 answers:
Answer:
190 pounds
Explanation:
Given that
A pound is approximately 0.45 kilogram
A person weighs 87 kilograms
Now change the unit form kilogram to pounds as follows:
1 pound / 0.45 kilogram * 87 kilograms
= 193.3 pounds
Now expressed to the correct number of significant figures
193.3 pound = 190 pounds
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Answer:
four (4)
Explanation:
Naphthalein is an organic compound with formula C 10H 8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs.
The molecule is planar, like benzene. Unlike benzene, the carbon–carbon bonds in naphthalene are not of the same length. The bonds C1−C2, C3−C4, C5−C6 and C7−C8 are about 1.37 Å (137 pm) in length, whereas the other carbon–carbon bonds are about 1.42 Å (142 pm) long. This difference, established by X-ray diffraction is consistent with the valence bond model in naphthalene and in particular, with the theorem of cross-conjugation. This theorem would describe naphthalene as an aromatic benzene unit bonded to a diene but not extensively conjugated to it (at least in the ground state), which is consistent with two of its three resonance structures.
Because of this resonance, the molecule has bilateral symmetry across the plane of the shared carbon pair, as well as across the plane that bisects bonds C2-C3 and C6-C7, and across the plane of the carbon atoms. Thus there are two sets of equivalent hydrogen atoms: the alpha positions, numbered 1, 4, 5, and 8, and the beta positions, 2, 3, 6, and 7. Two isomers are then possible for mono-substituted naphthalenes, corresponding to substitution at an alpha or beta position. Bicyclo[6.2.0]decapentaene is a structural isomer with a fused 4–8 ring system.
Therefore four (4) double bonds will be added to give each carbon atom an octet structure.
The accepted concentration of chlorine is 1.00 ppm that is 1 gram of chlorine per million of water.
The volume of water is .
Since, 1 gal= 3785.41 mL
Thus,
Density of water is 1 g/mL thus, mass of water will be .
Since, 1 grams of chlorine → grams of water.
1 g of water → g of chlorine and,
of water →86.6 g of chlorine
Since, the solution is 9% chlorine by mass, the volume of solution will be:
Thus, volume of chlorine solution is 9.62\times 10^{2} mL.