Can someone help me solve this? Thanks!

Why do A and T (and G and C) pair in a DNA double helix?

Usimov [2.4K]

I just took a quiz on this! It's D!

3 0

3 years ago

A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. A buffer region was found around

irinina [24]

Answer:

The unknown compound is a weak acid.

Explanation:

Given that :

a 25 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution.

A buffer region was found around a pH of 3.5. We know that a pH of 3.5 is a weak acid. So, it is likely to be an organic acid

Let assume the solution of the unknown sample to be CH₃COOH

Now :

25 mL of CH₃COOH reacted with 0.115 M of NaOH

The equation for the reaction will be :

CH₃COOH + NaOH -----> CH₃COONa + H₂O

at x mole of 0.115y M of

CH₃COOH NaOH is present

If NaOH was added in excess;

CH₃COOH + NaOH -----> CH₃COONa , NaOH will be lost then CH₃COOH and CH₃COONa will be present

Therefore;

At equilibrium : Only CH₃COONa will be present but if it is above equilibrium NaOH will be present because the pH will increase due to the presence of the strong base

8 0

4 years ago

Problem page in each of the molecules drawn below one chemical bond is colored red. decide whether this bond is likely to be pol

Slav-nsk [51]

The question is incomplete, here is the complete question:

Problem page in each of the molecules drawn below one chemical bond is colored red. Decide whether this bond is likely to be polar or not. if the bond is likely to be polar, write down the chemical symbol for the atom which will have more negative charge.

The image is attached below.

Answer:

For carbon dioxide molecule: The bond is considered as polar and the elecvtronegative atom is oxygen.

For water molecule: The bond is considered as polar and the elecvtronegative atom is oxygen.

Explanation:

There are two types of covalent bonds:

Polar covalent bond: This bond is formed when difference in electronegativity between the atoms is present. When atoms of different elements combine, it results in the formation of polar covalent bond. For Example: $CO_2,NO_2$ etc..
Non-polar covalent bond: This bond is formed when there is no difference in electronegativity between the atoms. When atoms of the same element combine, it results in the formation of non-polar covalent bond. For Example: $N_2,O_2$ etc..

In carbon dioxide molecule:

The given bond is present between C and O atom.

Electronegativity value of C = 2.5

Electronegativity value of O = 3.5

Electronegativity difference = (3.5 - 2.5) = 1

As, electronegativity difference is present. So, the bond is considered as polar and the elecvtronegative atom is oxygen.

In water molecule:

The given bond is present between H and O atom.

Electronegativity value of H = 2.1

Electronegativity value of O = 3.5

Electronegativity difference = (3.5 - 2.1) = 1.4

As, electronegativity difference is present. So, the bond is considered as polar and the elecvtronegative atom is oxygen.

8 0

4 years ago

Write the complete balanced equation for the following reaction:

Assoli18 [71]

Explanation:

An equation that consists of same number of atoms on both reactant and product side is known as a balanced chemical equation.

For example, $C_{7}H_{6}O + O_{2} \rightarrow CO_{2} + H_{2}O$

Number of atoms on reactant side are as follows.

C = 7

H = 6

O = 3

Number of atoms on product side are as follows.

C = 1

H = 2

O = 3

Therefore, to balance this chemical equation we multiply $O_{2}$ by 8 on reactant side. Whereas we multiply $CO_{2}$ by 7 and $H_{2}O$ by 3 on product side.

Therefore, the balanced chemical equation will be as follows.

$C_{7}H_{6}O + 8O_{2} \rightarrow 7CO_{2} + 3H_{2}O$

6 0

4 years ago

When the liquid state and the gaseous state of a substance are in equilibrium the rate of evaporation is?

butalik [34]

The rate of evaporation is equal to rate of condensation in equilibrium......It means the evaporation rate becomes constant.....And thus equilibrium attained !!!

8 0

3 years ago

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