Protons size and mass ?

For 100.0 mL of a solution that is 0.040M CH3COOH and 0.010 M CH3COO, what would be the pH after adding 10.0 mL 50.0 mM HCl?

damaskus [11]

Answer:

The pH of the buffer is 3.90

Explanation:

The mixture of a weak acid CH3COOH and its conjugate base CH3COO produce a buffer that follows the equation:

pH = pKa + log [A-] / [HA]

Where pH is the pH of the buffer, pKa is the pKa of acetic acid (4.75), and [A-] could be taken as the moles of the conjugate base and [HA] the moles of thw weak acid.

To solve this question we need to find the moles of the CH3COOH and CH3COO- after the reaction with HCl:

CH3COO- + HCl → CH3COOH + Cl-

The moles of CH3COO- are its initial moles - the moles of HCl added

And moles of CH3COOH are its initial moles + moles HCl added

Moles CH3COO-:

Initial moles = 0.100L * (0.010mol / L) = 0.00100moles

Moles HCl = 0.010L * (0.050mol / L) = 0.000500 moles

Moles CH3COO- = 0.000500 moles

Moles CH3COOH:

Initial moles = 0.100L * (0.040mol / L) = 0.00400moles

Moles HCl = 0.010L * (0.050mol / L) = 0.000500 moles

Moles CH3COO- = 0.003500 moles

pH is:

pH = 4.75 + log [0.000500] / [0.00350]

pH = 3.90

<h3>The pH of the buffer is 3.90</h3>

3 0

3 years ago

How many particles are present in 10.0 moles of table salt?

Dima020 [189]

1.01 x 10^24 molecules.

Explanation:

To calculate the number of molecules in a given number of mole, we can simply multiply by Avogadro's number which is equal to 6.022 x 10 ^23.

Therefore,

10 molecules = 1.68 mol x (6.022 x 10^23 molecules) / (1 mol = 1.01 x 10^24) molecules.

I hope this helps :)

7 0

3 years ago

Which properties change the composition of a substance?

Elanso [62]

Answer:

A.

Explanation:

Physical properties are characteristics of a substance that can be observed or measured without changing the composition of the substance. Some examples of physical properties are its volume and its density. There are two types of physical properties, intensive physical properties and extensive physical properties.

4 0

3 years ago

5

babymother [125]

Answer:

The total amount of mechanical energy is merely the sum of the potential energy and the kinetic energy. This sum is simply referred to as the total mechanical energy

4 0

3 years ago

assuming the magnesium ribbon wasn't sufficiently polished to remove a coating of magnesium oxie on the surface. how would this

Ira Lisetskai [31]

The magnesium ribbon wasn't sufficiently polished to remove a coating of magnesium oxie on the surface. how would this affect the volume of hydrogen gas produced? would this error cause the gas constant to be overestimated, underestimated, or remain unaffected?

1. Since, the magnesium ribbon wasn’t sufficiently polished to remove a coating of magnesium oxide on surface, the actual mass of magnesium taken will be less (as it also contains magnesium oxide). Hence, the number of moles of magnesium reacted and the number of moles of hydrogen produced will be less. Due to this, the volume of hydrogen gas produced will be less and the gas constant will be underestimated. R=\frac {PV}{nT} . Here n is calculated from weight of Mg taken but V is measured. Thus values of n will be same but the value of V will be lower. Hence, the value of R will be lower.

2. When droplets of water are remaining in the eudiometer tube, there volume will be added to the volume of hydrogen and the measured volume of hydrogen will be more than actual volume. Due to this, the value of the gas constant will be overestimated.

3. When small amount of hydrogen dissolves in water, the measured volume of hydrogen will be lower than the actual volume. This will underestimate the value of the gas constant.

4. When the temperature of the gas was underestimated, the value of the gas constant will be overestimated as the gas constant is inversely proportional to the temperature. {PV}

R=

{nT}.

Magnesium is a chemical detail with the symbol Mg and atomic number 12. it is a glittery gray solid which stocks many bodily and chemical residences with the alternative 5 alkaline earth metals (institution 2 of the periodic desk).

This element is produced in huge, growing old stars from the sequential addition of three helium nuclei to a carbon nucleus. whilst such stars explode as supernovas, a lot of the magnesium is expelled into the interstellar medium wherein it may recycle into new big name structures. Magnesium is the eighth maximum abundant element inside the Earth's crust and the fourth maximum not unusual detail in the Earth (after iron, oxygen and silicon), making up 13% of the planet's mass and a big fraction of the planet's mantle. it's miles the 0.33 maximum abundant detail dissolved in seawater, after sodium and chlorine.

Learn more about Magnesium here:-brainly.com/question/25860912

#SPJ4

8 0

1 year ago