Question

question 1 (1 point) saved
what part of the dna molecule is most exposed to the watery environment in the cell?
the flat, tightly stacked plates of the nucleotide bases
the ionically - charged phosphate groups in the \backbone\
the deoxyribose sugar alcohol groups in the \backbone\
the hydrogen - bonding links between nucleotides
question 2 (1 point) saved
most bacteria are
photosynthetic.
autotrophic.
heterotrophic.
chemolithotrophic.
question 3 (1 point) saved
the molecular weight of nacl is 58 grams per mole. a lab student dissolved 5.8 grams of nacl and brought the solution to one liter with water. the solution would have a molarity of
0.1 m.
1.0 m.
5.8 m.
10 m.

Explanation:

Step1: Calculate the number of moles of NaCl

The formula for calculating the number of moles \(n=\frac{m}{M}\), where \(m\) is the mass and \(M\) is the molar mass. Given \(m = 5.8\space g\) and \(M=58\space g/mol\), then \(n=\frac{5.8}{58}=0.1\space mol\)

Step2: Calculate the molarity

The formula for molarity \(C=\frac{n}{V}\), where \(n\) is the number of moles and \(V\) is the volume of the solution in liters. Given \(n = 0.1\space mol\) and \(V = 1\space L\), then \(C=\frac{0.1}{1}=0.1\space M\)

Answer:

Question 1: the ionically - charged phosphate groups in the "backbone"
Question 2: heterotrophic
Question 3: 0.1 M