Biology questions please help?

Question

1.) concerning amino groups which is a false statement?
they r basic in pH, found in amino acids, contain nitrogen, they r nonpolar, components of urea = i think it is the last one but not sure
2.) an example of a hydrogen bond is the bond between?
the H of one water molecule and the O of another molecule, Mg+ and Cl- in MgCl2, Na+ and Cl- in salt, two hydogen atoms in a molecule of hydrogen gas H2, C and H in methane CH4
3.) which of the following is possible due to high surface tension of water?
lakes dont freeze solid in winterdespite low temperatures, organisms resist temperature change although they give off heat due to chemical reactions, the pH of water remains exactly neutral, water can act as a solvent, a water strider can walk across the surface of a small pond
4.)what statement is completely correct?
H2CO3 is a weak acid and NaOH is a weak base, H2CO3 is a strong acid and NaOH is a strong base, NH3 weak base & HCI strong acid, NH3 weak base & H2CO3 strong acid

Answer 1

1) Amino groups have nitrogen. That's why it's called "amine." It has a N bonded to three things. They are a component of urea because urea has a N in it bonded to 2 H and the rest of the molecule. Urea = (NH2)2 CO. I don't think it's nonpolar. The amine has 3 things bonded to N plus a lone pair of electrons. It's going to end up having a dipole moment, so it's polar, in which case, being nonpolar is wrong I think.

2) Hydrogen bond, despite having the bond in its name, is NOT an actual bond. It's occurs between molecules, NOT within the molecule. THerefore, the first one is right. H of one water molecule being attracted to the O of another. The Mg+ and Cl- is an example of ionic bond. So is Na+ and Cl-. The bonds between the two H of H2 and the C and H are both covalent bonds.

3) High surface tension allows water striders to walk across the surface of a pond. Lakes don't freez solid in winter is due to the fact tha ice is less dense than water, not surface tension. Organism resisting temperature change is homeostasis. It might have to do with high heat capacity of water as well. The pH of water remaining neutral is because a neutral pH is defined to be the pH of water (ph = 7) assuming the water is pure. Water acting as a solvent has to do with polarity.

4) H2CO3 is carbonic acid, and it's not strong. If it were, your throat would burn if you drink soda. NaOH is not a weak base. The OH- is definitely not weak. NH3 is a weak base and HCl definitely strong, so that's the answer.

Hope this helps.

Answer 2

1) Amino groups are not non-polar.

2) H of 1 water molecule and O of another

3) water strider can walk across the pond

4) NH3 is weak base, HCl is strong acid.

Answer 3

1) amino groups are polar, so the non-polar choice is wrong
2) interaction between the H of one water and the O of another
3) water strider can walk across
4) not entirely sure. NaOH is a strong base and HCl is a strong acid for sure, but i'm never sure at which point something is a weak acid or base.

Answer 4

often, biology is in basic terms presented at grade 11 or higher, and many faculties would require student to have done grade 10 previous to taking grade 11 classes. Algebra is amazingly useful in both biology and chemistry because there are straight forward calculations that prefer to be done utilising one or 2 variables. solid math qualifications also provide a beginning for all technological information classes via good judgment and reasoning qualifications that flow alongside with it.

Answer 5

1 Don't know
2. water
3. strider
4. beats me