ANSWER FAST PLZ!!!!!!!!!

Paladinen [302]

Answer:

A

Explanation:

To answer this, we need to use Gay-Lussac's law, which states that:

$\frac{P_1}{T_1}= \frac{P_2}{T_2}$ , where P is pressure and T is temperature

The initial pressure we're given is 4.5 atm (so P1 = 4.5) and the temperature is 45.0°C; however, we need to change Celsius to Kelvins, so add 273 to 45.0: 45.0 + 273 = 318 K (so T1 = 318).

The final pressure is what we want to find, but we do know the final temperature is 3.1°C. Converting this to Kelvins, we get: 3.1 + 273 = 276.1 K, which means T2 = 276.1.

Plug these values in:

$\frac{P_1}{T_1}= \frac{P_2}{T_2}$

$\frac{4.5}{318}= \frac{P_2}{276.1}$

Multiply both sides by 276.1:

$P_2$ ≈ 3.9 atm

The answer is thus A.

3 0

3 years ago

A student notices that after two chemicals are mixed together the temperature of the mixture is higher than the temperature of t

swat32

Answer: exothermic

EXPLANATION: any process in which heat energy is released is called an exothermic process. For example burning of wood produces heat, so combustion of wood is an exothermic process.

When chemicals were not mixed they were at room temperature and when we mix them exothermic reaction took place and heat was released which raised the temperature of mixture.

7 0

3 years ago

The graph shows the speed of a car

Sav [38]

Answer:

Letter B.

Explanation:

Changing its direction and climbing a steep incline can't be proven only by the graph info. You can see that it's speed isn't constant in the graph.

We have letter B left.

6 0

3 years ago

You need to produce a buffer solution that has a pH of 5.31. You already have a solution that contains 10. mmol (millimoles) of

Karolina [17]

Answer:

37 mmol of acetate need to add to this solution.

Explanation:

Acetic acid is an weak acid. According to Henderson-Hasselbalch equation for a buffer consist of weak acid (acetic acid) and its conjugate base (acetate)-

$pH=pK_{a}(acetic acid)+log[\frac{mmol of CH_{3}COO^{-}}{mmol of CH_{3}COOH }]$

Here pH is 5.31, $pK_{a}$ (acetic acid) is 4.74 and number of mmol of acetic acid is 10 mmol.

Plug in all the values in the above equation:

$5.31=4.74+log[\frac{mmol of CH_{3}COO^{-}}{10}]$

or, mmol of $CH_{3}COO^{-}$ = 37

So 37 mmol of acetate need to add to this solution.

3 0

3 years ago

2. In Experiment SOL, you investigated the solubility of oxalic acid. Sodium oxalate, Na2C2O¬4, is the sodium salt of this acid.

AnnZ [28]

Answer:

Sodium oxalate is a basic salt. In water it can be dissolved and dissociated.

The oxalic acid in water has two dissociations.

Explanation:

Na2C2O4 ---> 2Na+ + C2O4-2

Sodium oxalate is the conjugate base of a weak acid. In water this salt, dissociates completely giving rise to the sodium and oxalate ions. As Na+ comes from a strong base, in water it does not produce hydrolysis while oxalate does react in water, because it takes a proton from it and it generates a basic hydrolysis releasing OH-.

C2O4-2 + H2O ⇄ HC2O4- + OH-

In water the salt is basic. The pH of an aqueous solution of this salt is basic, since OH- is generated.

The HC2O4- has a second hydrolisis, it takes another proton from water to form oxalic acid.

HC2O4- + H2O ⇄ H2C2O4 + OH-

The oxalic acid acts as a weak acid, it can release 2 protons to water, to make oxalate (its conjugate base).

H2C2O4 + H2O ⇄ H3O+ + HC2O4-

HC2O4- + H2O ⇄ H3O+ C2O4-2

The HC2O4- acts as an ampholyte since it accepts and delivers protons simultaneously.

6 0

3 years ago