Why is computational chemistry important?

During a lab activity, students prepared two solutions separately at the same temperature. Later they mixed the solutions and th

Yuri [45]

The temperature dropped because B. energy was absorbed during the chemical reaction.
If energy was released, the temperature would rise. If there was no energy input, the temperature would stay the same. Since temperature dropped, it means that energy was absorbed.

6 0

4 years ago

When a gas is dissolved in a liquid, what happens when the pressure

In-s [12.5K]

When gas is dissolved in a liquid, more gas dissolves into the liquid. It states that when the pressure of the gas when dissolved in liquid increases, the solubility increases. Thus, the correct option is C.

<h3>What is Pressure?</h3>

Pressure may be defined as the amount of force devoted perpendicular to the surface of an object per unit area. The unit of pressure is Pascal or Pa.

The solubility of any solution is directly proportional to the pressure that is exerted on it at a given time. As the pressure increases, more the solute dissolves into the solvent.

Therefore, the correct option for this question is C.

To learn more about Solubility, refer to the link:

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6 0

2 years ago

You measure 2.34 g of K2Cr2O7 into a volumetric flask. You dilute the K2Cr2O7 with water to a volume of 250 mL. It takes 35.7 mL

natta225 [31]

Answer:

0.191M of Na₂C₂O₄ is the concentration of the original Na₂C₂O₄ solution

Explanation:

The reaction of potassium dichromate, K₂Cr₂O₇ with sodium oxalate, Na₂C₂O₄ in the presence of acid H⁺ is:

K₂Cr₂O₇ + 3Na₂C₂O₄ + 14H⁺ → 2Cr³⁺ + 6CO₂ + 7H₂O + 6Na⁺ + 2K⁺

<em>Thus, 1 mole of K₂Cr₂O₇ reacts with 3 moles of Na₂C₂O₄</em>

Moles of 2.34g of K₂Cr₂O₇ (Molar mass: 294.185g/mol):

2.34g K₂Cr₂O₇ ₓ (1mol / 294.185g) = 7.954x10⁻³ moles K₂Cr₂O₇

In 250mL = 0.250L:

7.954x10⁻³ moles K₂Cr₂O₇ / 0.250L = 0.0318M K₂Cr₂O₇

Moles in 35.7mL = 0.0357L of this solution are:

0.0357L ₓ (0.0318mol / L) = <em>1.136x10⁻³ moles K₂Cr₂O</em>₇ in solution. As 1 mole of K₂Cr₂O₇ reacts with 3 moles of Na₂C₂O₄, to titrate the moles of K₂Cr₂O₇ in solution you need:

1.136x10⁻³ moles K₂Cr₂O₇ × (3 moles Na₂C₂O₄ / 1 mole K₂Cr₂O₇) =

<em>3.408x10⁻³ moles of Na₂C₂O₄</em>

In 17.8mL = 0.0178L:

3.408x10⁻³ moles of Na₂C₂O₄ / 0.0178L =

<h3>0.191M of Na₂C₂O₄ is the concentration of the original Na₂C₂O₄ solution</h3>

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3 0

3 years ago

A group of students is comparing the graphs of strong acid-strong base and weak acid-strong base titration curves, where the bas

erma4kov [3.2K]

The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve. Hence, option A is correct.

Weak acids are acids that don't completely dissociate in solution.

A weak acid is an acetic acid. It has a of 1.8⋅ $10^{-5}$ . Calculate how much it will dissociate in water. Since acetic acid is a weak acid so large part will not dissociate completely.

$k_a=\frac{[CH_3COO^-]H^+]}{[CH_3COOH]}$

B is not true, it shows the titration curve for weak/strong acid titrated with a strong base. When choosing an indicator for colourimetric titration select one so that the pH jump at the equivalence point contains the interval p±1. Phenolphthalein has a p≈9, so to decide if it is a suitable indicator check if the pH jumps from 8 to 10 at the equivalence point.

C is not true either because of the very slow reaction.

Learn more about weak acid here:

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5 0

2 years ago

Why is lithium used in the body?

Veronika [31]

Answer:

Lithium is used to treat mania that is part of bipolar disorder (manic-depressive illness). It is also used on a daily basis to reduce the frequency and severity of manic episodes.

8 0

4 years ago

Why is computational chemistry important?​

Why is computational chemistry important?