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3 years ago

Find the Volume.* Of a 3x3 cube

Mathematics

2 answers:

anzhelika [568]3 years ago

4 0

Answer:

either 9 or 27

Step-by-step explanation:

most likely 27 because 3x3x3

hram777 [196]3 years ago

4 0

Answer:

Cube number of 3 is 27

Step-by-step explanation:

cube of 3 is like 3×3×3 =27

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Ronch [10]

Answer:

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Step-by-step explanation:

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7 0

3 years ago

Read 2 more answers

Calculate the pH of a buffer solution made by mixing 300 mL of 0.2 M acetic acid, CH3COOH, and 200 mL of 0.3 M of its salt sodiu

Lesechka [4]

Answer:

Approximately $4.75$ .

Step-by-step explanation:

Remark: this approach make use of the fact that in the original solution, the concentration of $\rm CH_3COOH$ and $\rm CH_3COO^{-}$ are equal.

${\rm CH_3COOH} \rightleftharpoons {\rm CH_3COO^{-}} + {\rm H^{+}}$

Since $\rm CH_3COONa$ is a salt soluble in water. Once in water, it would readily ionize to give $\rm CH_3COO^{-}$ and $\rm Na^{+}$ ions.

Assume that the $\rm CH_3COOH$ and $\rm CH_3COO^{-}$ ions in this solution did not disintegrate at all. The solution would contain:

$0.3\; \rm L \times 0.2\; \rm mol \cdot L^{-1} = 0.06\; \rm mol$ of $\rm CH_3COOH$ , and

$0.06\; \rm mol$ of $\rm CH_3COO^{-}$ from $0.2\; \rm L \times 0.3\; \rm mol \cdot L^{-1} = 0.06\; \rm mol$ of $\rm CH_3COONa$ .

Accordingly, the concentration of $\rm CH_3COOH$ and $\rm CH_3COO^{-}$ would be:

$\begin{aligned} & c({\rm CH_3COOH}) \\ &= \frac{n({\rm CH_3COOH})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}$ .

$\begin{aligned} & c({\rm CH_3COO^{-}}) \\ &= \frac{n({\rm CH_3COO^{-}})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}$ .

In other words, in this buffer solution, the initial concentration of the weak acid $\rm CH_3COOH$ is the same as that of its conjugate base, $\rm CH_3COO^{-}$ .

Hence, once in equilibrium, the $\rm pH$ of this buffer solution would be the same as the ${\rm pK}_{a}$ of $\rm CH_3COOH$ .

Calculate the ${\rm pK}_{a}$ of $\rm CH_3COOH$ from its ${\rm K}_{a}$ :

$\begin{aligned} & {\rm pH}(\text{solution}) \\ &= {\rm pK}_{a} \\ &= -\log_{10}({\rm K}_{a}) \\ &= -\log_{10} (1.76 \times 10^{-5}) \\ &\approx 4.75\end{aligned}$ .

7 0

3 years ago

Gregorio took two tests. Find his z-score for each test. (Remember: The number of standard deviations between a score and the me

never [62]

I found the missing parts of this question.
Test A
Gregorio’s score 62 
Mean score 80 
Standard deviation 6 

Test B 
Gregorio's score 70 
Mean score 90 
Standard deviation 10 

a. Test A: 3; Test B: 2; Test A 
c. Test A: –2; Test B: –3; Test A 
b. Test A: –3; Test B: –2; Test B 
d. Test A: –3; Test B: –2; Test A


Refer to the attachment for the formula of z score:

test A: z = (62-80)/6 = -18/6 = -3
test B: z = (70-90)/10 = -20/10 = -2

B. Test A: –3; Test B: –2; Test B

5 0

3 years ago

Terri wants to put a fence around her tomato plants to keep the rabbits out. The hardware store only sells fencing in five-foot

Mice21 [21]

Answer: 30 increments

Step-by-step explanation: 150 divided by 5 is equal to 30. If she is buying in 5 foot increments she will need 30 five foot increments to have enough.

8 0

3 years ago

Twice as many students are in the chess club as in the fencing club.The number of students in the fencing club is one fifth the

jekas [21]

Answer:

28 students

Step-by-step explanation:

Let number of students in cooking club = x

Number of students in fencing club = 1/5 x

Number of students in chess club = 2(1/5)x

Since, There are 42 more students in the cooking club than in the chess club

Then ;

Number of students in chess club = Number of students in cooking club - 42

2(1/5)x = x - 42

(2/5)x - x = - 42

-0.6x = - 42

x = 42 / 0.6

x = 70

Hence, number of students in chess club :

(2/5) * 70 = 28

4 0

3 years ago