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Nadusha1986 [10]

3 years ago

8

What is the percent by mass of oxygen fe2o3 (formula mass= 160)?

1 answer:

GarryVolchara [31]3 years ago

5 0

30% should be the percentage of oxygen if the total mass of fe2o3 is 160.

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What affect does attendance have on students' grades in science class? Write the independent variable, the dependent variable, a

alexira [117]

Independent variable: the student chooses to miss class.
dependent variable: in result of the student missing class his grade goes down.
hyposthesis: if the student misses class multiple times, then his grades will go down.

6 0

3 years ago

What would a scientist’s next steps be if his/her data failed to support their hypothesis?

Paul [167]

To change only one variable which is very important than to test the experiment to match the hypothesis again, I think. It’s been a while since I was on that lesson‍♀️

6 0

3 years ago

Nitrites are commonly found in what food?

makvit [3.9K]

Ham, bacon, sausages, salami, pastrami, hot dogs, and other processed meat that is cured, smoked, or salted. The nitrite is used to preserve them.

7 0

3 years ago

Calculate the ph of a dilute solution that contains a molar ratio of potassium acetate to acetic acid (pka ???? 4.76) of (a) 2:1

givi [52]

According to Hasselbach-Henderson equation:

$pH=pK_{a}+log\frac{[A^{-}]}{[HA]}$

Here, $[A^{-}]$ is concentration of conjugate base and [HA] is concentration of acid.

In the given problem, conjugate base is $CH_{3}COOK$ and acid is $CH_{3}COOH$ thus, Hasselbach-Henderson equation will be as follows:

$pH=pK_{a}+log\frac{[CH_{3}COOK]}{[CH_{3}COOH]}$ ...... (1)

(a) Ratio of concentration of potassium acetate and acetic acid is 2:1 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=2$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{2}{1}=5.06$

Therefore, pH of solution is 5.06.

(b) Ratio of concentration of potassium acetate and acetic acid is 1:3 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=\frac{1}{3}$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{1}{3}=4.28$

Therefore, pH of solution is 4.28.

(c)Ratio of concentration of potassium acetate and acetic acid is 5:1 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=\frac{5}{1}$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{5}{1}=5.45$

Therefore, pH of solution is 5.45.

(d) Ratio of concentration of potassium acetate and acetic acid is 1:1 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=1$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{1}{1}=4.76$

Therefore, pH of solution is 4.76.

(e) Ratio of concentration of potassium acetate and acetic acid is 1:10 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=\frac{1}{10}$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{1}{10}=3.76$

Therefore, pH of solution is 3.76.

4 0

3 years ago

1. Una onda tiene una longitud de onda de 2 metros y una frecuencia de 1.5 Hz. ¿Cuál es su velocidad?

IrinaVladis [17]

Answer:

3 m/s

Explanation:

▲

usando la fórmula velocidad = frecuencia multiplicada por la longitud de onda.

v = (1.5)(2)

v= 3 m/s

6 0

3 years ago