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3 years ago

Which of the following did Antoine Lavoisier correctly characterize as an element?

2 answers:

8 0

I think the element that has been correctly defined by Antoine Lavoisier would be the element oxygen. He is famous for the discovery of the importance of the molecule oxygen in the process of combustion. He is is the one who characterized and named the element oxygen and hydrogen. Also, showing how these atoms combine in order to form a water molecule in the combustion process. He is considered as the father of modern chemistry as he helped in organizing nomenclature of the chemical compounds. He also is responsible for laying the foundations of the famous law of conservation of mass.

kotegsom [21]3 years ago

4 0

Answer:

Mercury

Explanation:

On Ed :)

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What is an easy way to measure the volume of an irregular shaped object?

pickupchik [31]

Answer: Water displacement

Explanation:

When you put an irregularly shaped object in a graduated cylinder, the water level rises. Subtract the original number of ml from the number of ml it was displaced, and you get its volume.

4 0

3 years ago

Why does mantle rock begin to sink back towards the lower mantle from the area closest to the crust?

Delvig [45]

Answer: Convection Currents

Explanation: The mantle rock is solid and denser because it is cooler. This means it will sink closer to lower mantle as warmer, lense dense rock/magma moves upwards.

8 0

3 years ago

An unknown diprotic acid (H2A) requires 44.391 mL of 0.111 M NaOH to completely neutralize a 0.58 g sample. Calculate the approx

Anna [14]

Answer:

$M=235.42g/mol$

Explanation:

Hello!

In this case, given this is an acid-base neutralization and we are considering a diprotic acid, we can write the following mole-mole relationship:

$2n_{acid}=n_{base}$

It means that the moles of acid can be computed given the volume and concentration of NaOH:

$n_{acid}=\frac{M_{base}V_{base}}{2} =\frac{0.044391L*0.111mol/L}{2} \\\\n_{acid}=2.46x10^{-4}mol$

It means that the approximate molar mass of the acid is:

$M=\frac{m_{acid}}{n_{acid}} \\\\M=\frac{m_{acid}}{n_{acid}} =\frac{0.58g}{2.46x10^{-3}mol}\\\\M=235.42g/mol$

Best regards!

5 0

3 years ago

For the generic equilibrium HA(aq) ⇌ H+(aq) + A−(aq), which of these statements is true? For the generic equilibrium , which of

timama [110]

<u>Answer:</u> The correct statement is if you add the soluble salt KA to a solution of HA that is at equilibrium, the pH would increase.

<u>Explanation:</u>

Common ion effect is defined as the effect which occurs on equilibrium when a common ion (an ion which is already present in the solution) is added to a solution. This effect generally decreases the solubility of a solute.

Equilibrium reaction of HA and KA follows the equation:

$HA\rightleftharpoons H^{+}(aq.)+A^{-}(aq.)$

$KA\rightleftharpoons K^+(aq.)+A^{-}(aq.)$

According to Le-Chateliers principle, if there is any change in the variables of the reaction, the equilibrium will shift in the direction in order to minimize the effect.

In the equilibrium reactions, $A^-$ ion is getting increased on the product side, so the equilibrium will shift in the direction to minimize this effect, which is in the direction of HA.

Thus, the addition of KA will shift the equilibrium in the left direction.

Equilibrium constant depends on the temperature of the system. It does not have any effect on any change of pH.

pH is defined as the negative logarithm of hydrogen ions present in the solution

If the solution has high hydrogen ion concentration, then the pH will be low.
If the solution has low hydrogen ion concentration, then the pH will be high.

As, the equilibrium is shifting in the left direction, that means concentration of $H^+$ ions are getting decreases. This will increase the pH of the solution.

Hence, the correct statement is if you add the soluble salt KA to a solution of HA that is at equilibrium, the pH would increase.

8 0

4 years ago

Why do we need to standardize EDTA in determination of water hardness?

bonufazy [111]

Standardized means that a specific amount EDTA is added to a specific volume of distilled water. Water hardness is determined by the the amount of a standard EDTA solution to change the color of the water from red to blue. For example if one added the correct amount of EDTA to twice the volume of distilled water the solution would be weak. Titration of the hard water would give a erroneous high result.

3 0

3 years ago