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4 years ago

Oxygen is an example of a(n)

Chemistry

1 answer:

stepladder [879]4 years ago

7 0

Answer:

C. element. oxygen is an element

Explanation:

oxygen is element #8

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Lithium acetate, LiCH3CO2, is a salt formed from the neutralization of the weak acid acetic acid, CH3CO2H, with the strong base

Vesna [10]

Answer : The pH of 0.289 M solution of lithium acetate at $25^oC$ is 9.1

Explanation :

First we have to calculate the value of $K_b$ .

As we know that,

$K_a\times K_b=K_w$

where,

$K_a$ = dissociation constant of an acid = $1.8\times 10^{-5}$

$K_b$ = dissociation constant of a base = ?

$K_w$ = dissociation constant of water = $1\times 10^{-14}$

Now put all the given values in the above expression, we get the dissociation constant of a base.

$1.8\times 10^{-5}\times K_b=1\times 10^{-14}$

$K_b=5.5\times 10^{-10}$

Now we have to calculate the concentration of hydroxide ion.

Formula used :

$[OH^-]=(K_b\times C)^{\frac{1}{2}}$

where,

C is the concentration of solution.

Now put all the given values in this formula, we get:

$[OH^-]=(5.5\times 10^{-10}\times 0.289)^{\frac{1}{2}}$

$[OH^-]=1.3\times 10^{-5}M$

Now we have to calculate the pOH.

$pOH=-\log [OH^-]$

$pOH=-\log (1.3\times 10^{-5})$

$pOH=4.9$

Now we have to calculate the pH.

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-4.9=9.1$

Therefore, the pH of 0.289 M solution of lithium acetate at $25^oC$ is 9.1

4 0

4 years ago

If it takes 7,529 calories of heat to warm 750.0 grams of water, what was the temperature change? The specific heat of water in

Zigmanuir [339]

Answer:

The temperature change was 10.04 °C.

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system. In this way, there is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:

Q = c * m * ΔT

Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case you know:

Q= 7,529 calories (cal)

c= 1 $\frac{cal}{g*C}$

M=750 grams

Replacing:

7,529 cal= 1 $\frac{cal}{g*C}$ *750 g* ΔT

Solving you get:

ΔT= $\frac{7,529 cal}{1 \frac{cal}{g*C}*750 g }$

ΔT= 10.04 °C

So, the temperature change was 10.04 °C.

6 0

3 years ago

Read 2 more answers

Adaptation: Question 1 Which best explains why a population of a certain species of moose , over five generations , developed fe

slamgirl [31]

Answer:

im doing this test lol

Explanation:

what is it?

4 0

3 years ago

a student determined in the laboratory that the percent by mass of water in cus04 5h20 is 38.0% if the accepted value is 40% wha

IrinaVladis [17]

Percent error is [(abs(experimental - actual))/(actual)] * 100
(38.0 - 40.0 ) / 40.0 = 2.0 / 40 = 0.05
0.05 * 100 = 5
since there are 2 sigfigs, the answer is 5.0 %

I made the 2 positive since the absolute value of 38.0 - 40.0 was taken
There are only 2 sigfigs because of the subtraction of 38.0 - 40.0 gives 2.0, only 2 sigfigs

4 0

4 years ago

A: -3.45 B: 17.45 C: 10.55 D: 3.55

Minchanka [31]

Answer:

i think its b

Explanation:

6 0

4 years ago