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valentina_108 [34]

3 years ago

11

Which of the following sentence best describes a buffer? A. Buffer is A substance that resists small change in the acidity of a

solution when an acid or base is added to the solution.
B. A chemical substance that prevents changes in hydrogen ion concentration.

1 answer:

vovangra [49]3 years ago

6 0

The correct answer is A. A buffer is a substance that resists small change in the acidity of a solution when an acid or base is added to the solution. Usually, a buffer involves a weak acid or a weak alkali and one of its salt.

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A certain alcohol contains only three elements, carbon, hydrogen, and oxygen. Combustion of a 60.00 gram sample of the alcohol p

marin [14]

Answer:

$C_2H_6O$

Explanation:

The first step is the <u>calculation of the moles</u> of $H_2O$ and $CO_2$ , so:

$114.6~g~CO_2\frac{1~mol~CO_2}{44~g~CO_2}=2.6~mol~of~CO_2$

$70.44~g~H_2O\frac{1~mol~H_2O}{18~g~H_2O}=~3.9~mol~H_2O$

Now, in 1 mol of CO2 we have 1 mol of C and in 1 mol of $H_2O$ we have 1 mol of H. Additionally, if we want to calculate the moles of oxygen we need to <u>calculate the grams of C and O</u> and then do the <u>substraction</u> form the initial amount, so:

$2.6~mol~CO_2\frac{1~mol~C}{1~mol~CO_2}\frac{12~g~C}{1~mol~C}=31.25~g~of~C$

$3.9~mol~H_2O\frac{2~mol~H}{1~mol~H_2O}\frac{1~g~H}{1~mol~H}=7.82~g~of~H$

$Total~grams=~31.25~+~7.82=39.08~g$

$grams~of~O=60.00~g-~39.08~g=20.92~g~of~O$

Now we can <u>convert the grams</u> of O to moles, so:

$20.92~g~of~O\frac{1~mol~O}{16~g~O}=1.30~mol~O$

The next step is to divide all the mol values by the <u>smallest one</u>:

$O=\frac{1.30~mol~O}{1.30~mol~O}=~1$

$C=\frac{2.6~mol~C}{1.30~mol~O}=~2$

$H=\frac{7.82~mol~H}{1.30~mol~O}=6$

Therefore the formula is $C_2H_6O$

6 0

3 years ago

Enlista cuatro compuestos del carbono,naturales y sintéticos,de uso en la vida cotidiana.

Mice21 [21]

Below is the list of both Natural and Synthetic compounds containing Carbon.

Natural Compounds Containing Carbon:

1) Food:
Carbohydrates, Proteins, Lipids, Fibers

  2) Clothing:
Silk, Wool, Cotton

    3) Transportation:
Coal, Natural Gas, Petroleum

  4) Wood:
Building, Furniture

Synthetic Compounds Containing Carbon:

1) Clothing:
  Nylon, Polyester,

    2) Transportation:
Petrol, Diesel, Jet Fuels

  3) Building:
High Density Polyethylene, Polyvinyl Chloride

  4) Home Appliances:
Teflon in non-stick Pans, polyethylene terephthalate bottles

5 0

3 years ago

Read 2 more answers

Which of the following properties of a protein is least likely to be affected by changes in pH? Tertiary structure Primary struc

chubhunter [2.5K]

Answer:

Primary structure is the correct answer.

Explanation:

The primary structure is the simple level of protein structure.

Primary structure is a basic amino acids sequences in a protein.

In the primary structure, amino acids are attached together by a covalent bond.
Primary structure is when the amino acids are joined together with peptide bonds to produce polypeptide chains

Changes in pH are least likely to change the amino acid sequence or disrupt peptide bonds.

Explanation:

7 0

3 years ago

If liquid water is exposed to normal atmospheric pressure, what needs to change in order to change its state of matter?

inn [45]

Answer: Option (b) is the correct answer.

Explanation:

State of a substance changes when heat is provided to a substance.

This is because when we heat water then intermoleclar forces present within its molecules tend to break down. Due to this molecules start to move away from each other.

As a result, kinetic energy of molecules increases and they collide rapidly. Hence, solid state of water changes into liquid state and upon excessive heating liquid state of water changes into vapor state.

Thus, we conclude that temperature of water needs to change in order to change its state of matter.

6 0

3 years ago

Read 2 more answers

Determine the value of the equilibrium constant, KgoalKgoalK_goal, for the reaction CO2(g)⇌C(s)+O2(g)CO2(g)⇌C(s)+O2(g), Kgoal=?

NISA [10]

Answer:

The value of the equilibrium constant for reaction asked is $1.24\times 10^{-7}$ .

Explanation:

$CO_2(g)\rightleftharpoons C(s)+O_2(g)$

$K_{goal}=?$

$K_{goal}=\frac{[C][O_2]}{[CO_2]}$

$2CO_2(g)+2H_2O(l)\rightleftharpoons CH_3COOH(l)+2O_2(g)$ ..[1]

$K_1=\frac{[CH_3COOH][O_2]^2}{[CO_2]^2[H_2O]^2}$

$2H_2(g)+O2(g)\rightleftharpoons 2H_2O(l)$ ..[2]

$K_2=\frac{[H_2O]^2}{[H_2]^2[O_2]}$

$CH_3COOH(l)\rightleftharpoons 2C(s)+2H_2(g)+O_2(g)$ ..[3]

$K_3=\frac{[C]^2[H_2]^2[O_2]}{[CH_3COOH]}$

[1] + [2] + [3]

$2CO_2(g)\rightleftharpoons 2C(s)+2O_2(g)$

( on adding the equilibrium constant will get multiplied with each other)

$K=K_1\times K_2\times K_3$

$K=5.40\times 10^{-16}\times 1.06\times 10^{10}\times 2.68\times 10^{-9}$

$K=1.53\times 10^{-14}$

$K=\frac{[C]^2[O_2]^2}{[CO_2]^2}$

On comparing the K and $K_{goal}$ :

$K^2=K_{goal}$

$K_{goal}=\sqrt{K}=\sqrt{1.53\times 10^{-14}}=1.24\times 10^{-7}$

The value of the equilibrium constant for reaction asked is $1.24\times 10^{-7}$ .

4 0

3 years ago