Which element has a greater ionization energy, rubidium or iodine?

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

Which chemical is the reducing agent in the redox reaction below?

posledela

Option (a) is correct.

A reducing agent is the one which loses electrons to other substance.

Here, Zn has oxidation number 0 in the L.H.S of the equation, but on R.H.S its oxidation number is +2 i.e. it Zn has donated two of its electrons to $Fe^{2+}$ .

Hence, Zn is the reducing agent here.

6 0

2 years ago

What element is helpful for tooth decay

emmainna [20.7K]

Fluoride and calcium are both helpful for stopping tooth decay

3 0

3 years ago

Find the number of grams 4.00 moles of CU(CN)2

USPshnik [31]

Answer:

462g

Explanation:

First, let us calculate the molar mass of Cu(CN)2. This is illustrated below:

Molar Mass of Cu(CN)2 = 63.5 + 2(12+14) = 63.5 + 2(26) = 63.5 + 52 = 115.5g/mol

Number of mole of Cu(CN)2 given from the question = 4moles

Mass = number of mole x molar Mass

Mass of Cu(CN)2 = 4 x 115.5

Mass of Cu(CN)2 = 462g

4 0

2 years ago

Identify the compound with the smallest dipole moment in the gas phase. identify the compound with the smallest dipole moment in

stepladder [879]

Without solving for the dipole moment, we can easily determine which among the common gases has the smallest dipole moment just by determining the differences in their electronegativity. The greater the difference in the electronegativity, the higher is the value of the dipole moment.

From the given above, there are obvious differences between the electronegativity between the atoms composing LiF, ClF, and HF. For Cl2, since this is the same molecule then, the difference in the electronegativity is zero.

Answer: Cl2.

3 0

2 years ago