Question 2 (20 points)

Which of these statements is not true about chemical reaction rates?

Sliva [168]

I think it is A. The reaction rates can change.
I think we all know that B. and C. are incorrect, but I took a science lesson about this and it specifically said that on a graph of a rate, a curved line is NOT constant, meaning it is possible to not be constant.

8 0

3 years ago

Read 2 more answers

The Henderson-Hasselbalch equation relates the pH of a buffer solution to the pKa of its conjugate acid and the ratio of the con

Kobotan [32]

Answer:

The correct answer is 190.5 mL of 1.00 M KH₂PO₄

Explanation:

A phosphate buffer is composed by phosphate acid (KH₂PO₄) and its conjugated base (K₂HPO₄). To obtain the relation between the concentrations of base and acid to add, we use Henderson-Hasselbach equation:

pH= pKa + log $\frac{base}{acid}$

We have: pH= 6.97 and pKa= 7.21. So, we replace the values in the equation:

6.97= 7.21 + log $\frac{base}{acid}$

6.97-7.21= log $\frac{base}{acid}$

-0.24= log $\frac{base}{acid}$

$10^{-0.24}$ = $\frac{base}{acid}$

0.575 = $\frac{base}{acid}$

$\frac{0.575}{1}$ = $\frac{base}{acid}$

It means that you have to mix a volume 0.575 times of conjugated base and 1 volume of acid. If we assume a total buffer concentration of 1 M, we have:

base + acid = 1

base= 1 - acid

We replace in the previous equation:

0.575= $\frac{1-acid}{acid}$

0.575 acid= 1 - acid

0.575 acid + 1 acid= 1

1.575 acid = 1

acid= 1/1,575

acid= 0.635

base= 1 - acid = 1 - 0.635 = 0.365

For a total volume of 300 ml, the volumes of both acid and base will be:

300 ml x 0.635 M = 190.5 ml of acid (KH₂PO₄)

300 ml x 0.365 M= 109.5 ml of base (K₂HPO₄)

We can corroborate our calculations as follows:

190.5 ml + 109.5 ml = 300 ml

109.5 ml / 190.5 ml = 0.575

4 0

3 years ago

How do I balance these equations

Svet_ta [14]

Easy you can't touch the subscripts so u need to add coiffents like a puzzle if you do this then it will chance this 1st name each element on each side then say how much it's worth then see what you need to chance like this
Ti=1
Cl=4
Mg=1.
On the other side

Ti=1
Mg=1
Cl=2. What do you need to change using coffients

8 0

3 years ago

A student observes the chemical process described by this equation:

choli [55]

Answer:

Both are equal

Explanation:

Mass of starting material i.e Aluminium is $4.480 * 10^{-23}$ grams