# Tutor profile: Kevin N.

## Questions

### Subject: Chemistry

which of the following intermolecular forces result in a higher boiling point? A. London Dispersion Force B. Hydrogen Bonding C. Dipole-Dipole D. Phosphodiester bond

A. Not correct. London Dispersion forces are the weakest of all the intermolecular forces. Every molecule has them. These forces are stronger with bulkier atoms. B. CORRECT. Hydrogen bonds are strong and they are difficult to break. More hydrogen bonds will make it harder for a liquid to boil because the forces that hold them together are hydrogen bonds, making them strong. C. Not correct. Dipole-Dipole is a strong intermolecular force. But, if there was an ion-dipole force, this would be stronger than a hydrogen bond. D. Not correct. This is not a form of intermolecular force. Phosphodiester bonds are commonly seen in DNA and RNA in which the sugars are attached by.

### Subject: Biology

Tay-Sachs disease is inherited as an autosomal recessive. In a certain large eastern European population, the frequency of Tay-Sachs disease is 1 percent. a) If the population is assumed to be in Hardy-Weinberg equilibrium with respect to Tay-Sachs, what is the frequency of the allele that causes Tay-Sachs? b) What would be the frequency of heterozygotes? c) What is the probability of two heterozygotes marrying?

a) q = $$\sqrt{.01}=.1$$ b) $$ 2 x 0.9 x 0.1 = .18$$ c) $$(.18)^2$$ = $$.032$$

### Subject: Algebra

If $$ 2x-3(x+4) = -5 $$ then $$ x = $$

$$ 2x-3(x+4) = -5 $$ $$ 2x - 3x -12 = -5 $$ --- you must add 12 to both sides $$ 2x - 3x = 7 $$ $$ (2-3)x = 7 $$ --- $$2x - 3x$$ is the same as $$(2-3)x$$. Both 2 and 3 have the variable. $$ (-1)x = 7 $$ --- you divide by $$-1$$ on both sides. $$ x = -7 $$ --- dividing a positive by a negative gives you a negative answer

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