Calculate the volume of an object with dimensions measuring 3.o cm x 4.0 cm x 1.0 cm<br> ?cm^3

The active ingredient in aspirin is acetylsalicylic acid. A 2.79 g sample of acetylsalicylic acid required 30.15 mL of 0.5137 M

vivado [14]

Answer:

Molar mass = 180 g/mol

Ka = 3.31x10⁻⁴

Explanation:

Because the acetylsalicylic is a monoprotic acid, it only leaves 1 mol of H⁺ in the reaction, so, it's necessary 1 mol of NaOH for each 1 mol of acetylsalicylic acid. The number of moles of NaOH is the volume, in L, multiplied by the concentration:

n = 0.03015*0.5137 = 0.01549

Which is also the number of moles of the acid. The molar mass is the mass, in g, divided by the number of moles:

M = 2.79/0.01549

M = 180 g/mol

After reacting with the base, the conjugate base of the acid will be formed, and the equilibrium between the acid form (HA) and the conjugate base (A⁻) is a buffer. It formed 0.01549 moles of A⁻, which will react with the moles of H⁺ from HCl to form HA.

nH⁺ = nHCl = 0.01741*0.448 = 0.0078 mol

A⁻ + H⁺ ⇄ HA

0.01549 0.0078 0 Initial

-0.0078 -0.0078 +0.0078 Reacts

0.0078 0 0.0078 Equilibrium

For a buffer, the pH can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[A⁻]/[HA]

Because the volume is the same, we can use the number of moles instead of the concentration:

3.48 = pKa + log(0.0078/0.0078)

pKa = 3.48

pKa = -logKa

Ka = $10^{-pKa}$

Ka = $10^{-3.48}$

Ka = 3.31x10⁻⁴

5 0

3 years ago

PLEASE HELP I WILL REWARD BRAINLIEST !!!

Travka [436]

Googles Definition of Convection: <span>the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

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4 0

3 years ago

What is the pH of this solution?

Vesnalui [34]

Answer:

pH = 11.216.

Explanation:

Hello there!

In this case, according to the ionization of ammonia in aqueous solution:

$NH_3+H_2O\rightleftharpoons NH_4^++OH^-$

We can set up its equilibrium expression in terms of x as the reaction extent equal to the concentration of each product at equilibrium:

$Kb=\frac{[NH_4^+][OH^-]}{[NH_3]} \\\\1.80x10^{-5}=\frac{x*x}{0.150-x}$

However, since Kb<<<1 we can neglect the x on bottom and easily compute it via:

$1.80x10^{-5}=\frac{x*x}{0.150}\\\\x=\sqrt{1.80x10^{-5}*0.150}=1.643x10^{-3}M$

Which is also:

$[OH^-]=1.643x10^{-3}M$

Thereafter we can compute the pOH first:

$pOH=-log(1.643x10^{-3}M)\\\\pOH=2.784$

Finally, the pH turns out:

$pH=14-2.784\\\\pH=11.216$

Regards!

5 0

3 years ago

A galvanic cell consists of a Cu(s)|Cu2+(aq) half-cell and a Cd(s)|Cd2+(aq) half-cell connected by a salt bridge. Oxidation occu

Kryger [21]

Answer:

$Cd(s)|Cd^{2+}(aq) || Cu^{2+}(aq)|Cu(s)$

Explanation:

A galvanic cell is composed of two electrodes immersed in a suitable electrolyte and connected via a salt bridge. One of the electrodes serves as a cathode where reduction or gain of electrons takes place. The other half cell functions as an anode where oxidation or loss of electrons occurs.

The representation is given by writing the anode on left hand side followed by its ion with its molar concentration. It is followed by a salt bridge. Then the cathodic ion with its molar concentration is written and then the cathode.

As it is given that cadmium acts as anode, it must be on the left hand side and copper must be on right hand side.

$Cd(s)|Cd^{2+}(aq) || Cu^{2+}(aq)|Cu(s)$

6 0

3 years ago

The coefficients in a balanced chemical equation represent

Dafna1 [17]

The coefficients in a chemical equation represent the molar ratio of the substances.

For example, if an equation says 2H2 + O2 ⇒ 2H2O, it means
2 moles of H2 + 1 mol of O2 ⇒ 2 moles of H2O.

8 0

3 years ago

Calculate the volume of an object with dimensions measuring 3.o cm x 4.0 cm x 1.0 cm ?cm^3