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3 years ago

Which of these substances acts as a buffer? a. blood b. lemon juice c. curd

1 answer:

7 0

The correct answer is( A) blood.

when the buffer solution its PH value changes very little when a small amount

of strong acid or base is added to it, and here the bicarbonate buffering system is used to regular the PH of the blood that keeping the PH at nearly constant value by maintaining the original acidity or basicity of the solution.

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Which elements have two valence electrons?

lora16 [44]

Answer:

Magnesium

Explanation:

Magnesium is in group 2 of the periodic table. The group in which an element is found in tells us the number of valence eletrons it has.

HOPE THIS HELPED

7 0

3 years ago

A chemist titrates 160.0mL of a 0.3403M aniline C6H5NH2 solution with 0.0501M HNO3 solution at 25°C . Calculate the pH at equiva

maxonik [38]

Answer : The pH of the solution is, 5.24

Explanation :

First we have to calculate the volume of $HNO_3$

Formula used :

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the initial molarity and volume of $C_6H_5NH_2$ .

$M_2\text{ and }V_2$ are the final molarity and volume of $HNO_3$ .

We are given:

$M_1=0.3403M\\V_1=160.0mL\\M_2=0.0501M\\V_2=?$

Putting values in above equation, we get:

$0.3403M\times 160.0mL=0.0501M\times V_2\\\\V_2=1086.79mL$

Now we have to calculate the total volume of solution.

Total volume of solution = Volume of $C_6H_5NH_2$ + Volume of $HNO_3$

Total volume of solution = 160.0 mL + 1086.79 mL

Total volume of solution = 1246.79 mL

Now we have to calculate the Concentration of salt.

$\text{Concentration of salt}=\frac{0.3403M}{1246.79mL}\times 160.0mL=0.0437M$

Now we have to calculate the pH of the solution.

At equivalence point,

$pOH=\frac{1}{2}[pK_w+pK_b+\log C]$

$pOH=\frac{1}{2}[14+4.87+\log (0.0437)]$

$pOH=8.76$

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-8.76\\\\pH=5.24$

Thus, the pH of the solution is, 5.24

4 0

3 years ago

If a dog has a mass of 21.5kg, what is his mass in the following units?

PolarNik [594]

Answer: 21.5kg in grams is 21,500 grams

21.5kg in mg is 215,000,00

Explanation:

5 0

3 years ago

Please I really really need help!!!

ira [324]

Answer:

1) 40

2) 2.25 moles

3) 17

4) 120

5) Fe₂O₃

Explanation:

Please see attached picture for full solution.

6 0

3 years ago

Read 2 more answers

CO2+2H2O=H3O^++HCO3^-

bekas [8.4K]

Answer:

Bronsted Lowry Theory

$CO_2$ is the acid

$H_2 O$ is the base

$H_3 O^+$ is the conjugate acid and

$HCO_3^-$ is the conjugate base

Explanation:

Bronsted Lowry Theory:

An acid is a substance that can donate one or more protons

A base is a substance which can accept one or more protons

Hydrogen atom which is neutral (No Charge) contains 1 positive proton, 1 negative electron and 0 neutral neutron.

Thus Hydrogen atom has no Charge and it is neutral.

When an hydrogen atom loses an electron, Hydrogen ion is formed, which will contain 1 positive proton and 0 negative electron and 0 neutral neutron.

Thus Hydrogen ion has a positive charge.

Hydrogen ion is also called as a proton since it has only 1 proton in it.

Hydrogen ion in water that is,

$H^++H_2O\Rightarrow H_3O^+$

$H_3O^+$ is called as Hydronium ion.

Acid loses H+ (proton) to form conjugate Base

Base gains H+ (proton) to form conjugate Acid

For example

Let us consider the example given in the question

$CO_2+2H_2 O>H_3 O^+ +HCO_3^-$ can be written as (removed 1 $H_2 O$ from both the sides )

$CO_2+H_2 O>H^++HCO_3^-$ or

$CO_2+H_2 O > H_2 CO_3$ reversing the equation

$H_2 CO_3+H_2 O>H_3 O^+ +HCO_3^-$

$H_2 CO_3$ is the acid which donates $H^+$ to form $HCO_3^-$

$H_2 O$ is the base which gains $H^+$ to form $H_3 O^+$

$HCO_3^-$ is the conjugate base and $H_3 O^+$ is the conjugate acid

$CO_2$ is the acid

$H_2 O$ is the base

$H_3 O^+$ is the conjugate acid and

$HCO_3^-$ is the conjugate base

(Answer)

5 0

3 years ago