Iron is a mineral. A nail made out of iron a mineral. Answers: Is also Is not

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with

Liula [17]

Answer:

8.0 moles

Explanation:

Since the acid is monoprotic, 1 mole of the acid will be required to stochiometrically react with 1 mole of NaOH.

Using the formula: $\frac{concentration of acid X volume of acid}{concentration of base X volume of base} = \frac{mole of acid}{mole of base}$

Concentration of acid = ?

Volume of acid = 10 mL

Concentration of base = 1.0 M

Volume of base = 40 mL

mole of acid = 1

mole of base = 1

Substitute into the equation:

$\frac{concentration of acid X 10}{1.0 X 40} = \frac{1}{1}$

Concentration of acid = 40/10 = 4.0 M

To determine the number of moles of acid present in 2.0 liters of the unknown solution:

Number of moles = Molarity x volume

molarity = 4.0 M

Volume = 2.0 Liters

Hence,

Number of moles = 4.0 x 2.0 = 8 moles

8 0

3 years ago

The pH at the midpoint in the titration of an acid with a base is A) equal to the pK of the corresponding base. B) equal to the

iVinArrow [24]

Answer:

The pH at the midpoint in the titration of an acid with a base is

A) equal to the pK of the corresponding base.

B) equal to the pK of the corresponding acid.

C) equal to 14 minus the pK of the corresponding acid.

D) equal to 14 plus the pK of the corresponding base.

E) none of the above

Explanation:

When a weak acid is titrated with a strong base, then a buffer solution is formed.

pH of a buffer solution can be calculated by using the formula:

$pH=pKa+log\frac{[salt]}{[acid]}$

Exactly at the mid point,

[conjugate base of the salt]=[acid]

So, log [salt]/[acid] =0

Hence, pH of the solution will be equal to pKa of the weak acid.

Answer is option B.

6 0

3 years ago

Ethanol (c2h5oh) melts at -114c and boils at 78 c the enthalpy of fusion of ethanol is 5.02 kj/mol, and its enthalpy of vaporiza

vovikov84 [41]

100 kilo joules There are several phases that this problem undergoes and the final answer is the sum of all the energy used for each phase. Phase 1. Heating of solid ethanol until its melting point. Phase 2. Melting of the ethanol until it's completely liquid. Phase 3. Heating of the liquid ethanol until it reaches its boiling point. Phase 4. Boiling the ethanol until it's completely vapor. To make things more interesting, some of our constant are per gram and some others are per mole. So let's calculate how many moles of ethanol we have. Atomic weight carbon = 12.0107 Atomic weight hydrogen = 1.00794 Atomic weight oxygen = 15.999 Molar mass ethanol = 2*12.0107 + 6*1.00794 + 15.999 = 46.06804 g/mol Moles ethanol = 75g / 46.06804 g/mol = 1.628026719 mol Phase 1. Use the specific heat of solid ethanol and multiply by the number of degrees we need to change by the mass we have. So 0.97 J/g*K * 75 g * (-114c - -120c) = 0.97 J/g*K * 75 g * 6K = 436.5 J Phase 2: Time to melt. Just need the moles and the enthalpy of fusion. So: 1.628026719 mol * 5.02 kJ/mol = 8.172694128 kJ Phase 3: Heat to boiling. Just like heating to melting, just a different specific heat and temperature 2.3J/g*K * 75g * (78c - -114c) = 2.3J/g*K * 75g * 192 K = 33120 J Phase 4: Boil it to vapor. Need moles and enthalpy of vaporization. So 1.628026719 mol * 38.56 kJ/mol = 62.77671027 kJ Now let's add them together: 436.5 J + 8.172694128 kJ + 33120 J + 62.77671027 kJ = 0.4365 kJ + 8.172694128 kJ + 33.120 kJ + 62.77671027 kJ =104.5059044 kJ Since the least precise datum we have is 2 significant figures, round the result to 2 significant figures, giving 100 kilo joules.

3 0

3 years ago

The absorbance of a crystal violet solution in water (density is 1.00 g/mL) is measured in a 1.0 cm cuvette. The absorbance is 0

spin [16.1K]

Answer : The molar concentration of solution is $7.06\times 10^{-6}mol/L$

Explanation :

Using Beer-Lambert's law :

$A=\epsilon \times C\times l$

where,

A = absorbance of solution = 0.614

C = molar concentration of solution = ?

l = path length = 1.0 cm

$\epsilon$ = molar absorptivity coefficient = $87000M^{-1}cm^{-1}$ (assume)

Now put all the given values in the above formula, we get:

$0.614=(87000M^{-1}cm^{-1})\times C\times (1.0cm)$

$C=0.00000705747mol/L=7.06\times 10^{-6}mol/L$

Therefore, the molar concentration of solution is $7.06\times 10^{-6}mol/L$

4 0

3 years ago

What is the most common state of matter?

schepotkina [342]

Matter in the plasma state has variable volume and shape, but as well as neutral atoms, it contains a significant number of ions and electrons, both of which can move around freely. Plasma is the most common form of visible matter in the universe. The four fundamental states of matter.

5 0

3 years ago