Tutor profile: Lilyossa M.

3-(-5+2)x3

According to BODMAS rule, we first need to deal with the bracket: -5+2=-3 Thereafter, we need to multiply the answer we got in the bracket by 3: -3x3=-9 Now we can subtract -9 from 3: 3-(-9) here we have a negative and a negative following each other so that means it becomes a positive: 3+9=12. Therefore, our final answer is 12.

Why would ethanol have a higher boiling point than ethane?

Ethanol is an alcohol while ethane is an alkane. Alkanes only have London (induced dipole or dispersion) forces while alcohols have both London forces and hydrogen bonds which are stronger than London forces. Hence alcohols will have stronger intermolecular forces than alkanes and will require more energy in order to be able to break these intermolecular forces and that is why ethanol has a greater boiling point than ethane.

Miles comes into the hospital with unusual bruises and bleeding all over his body. His doctor diagnoses him with hemophilia, an inherited disorder. None of his other siblings, which are all girls, have the disorder but his grandfather on his mother's side has it. How did he get hemophilia and why is it that he, and not his sisters, was affected with the condition?

Hemophilia is an X-linked recessive condition, meaning that it is inherited on the X-chromosome and in order for one to express it, especially in the case of females, you need to have two copies of the mutated (defective) hemophilia gene. Males only have one X-chromosome and that is why it is common for them to have hemophilia because they only need to inherit one defective chromosome from one parent in order to get hemophilia while it's harder for girls to get hemophilia because they need to inherit two defective genes on both X-chromosomes from both parents in order to express the condition. Because the grandfather has hemophilia, he passed on the defective X-chromosome to his daughter, Miles' mother who is an obligate carrier and there is a 50% chance that she can pass this defective chromosome to one of her children. If the girls get it, they become carriers and do not get the disease because they have another normal X-chromosome that can compensate for the abnormal one. In the case of males, once they get the defective chromosome, there is not another X-chromosome to compensate for that dysfunctional one and so they get the disease.