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11111nata11111 [884]

3 years ago

13

What is an ice age?

2 answers:

enyata [817]3 years ago

7 0

An ice age was when the temperature was cold and lots of animals lived there So B

blondinia [14]3 years ago

5 0

The answer would be B

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A 0.5 mol sample of He(g) and a 0.5 mol sample of Ne(g) are placed separately in two 10.0 L rigid containers at 25°C. Each conta

KiRa [710]

Answer:

Helum (He)g will escape faster

Explanation:

the phenomemenon can be explained by the Graham's law of diffusion.

Graham's law of difussion states that the rate of difussion is inversely proportional to the square root of the molecular mass,which means the gas with lower molecular mass will escape faster.

Helium gas has a molecular mass of 4 while Neon has a molecular mass of 10.

rate of diffusion of He/rate of difussion of Ne=√4/10=√0.4=0.63

It means He(g) will move 0.63 times faster than Ne(g) under the same condition

5 0

3 years ago

You determine that it takes 26.0 mL of base to neutralize a sample of your unknown acid solution. The pH of the solution was 7.8

Lubov Fominskaja [6]

Complete Question

You determine that it takes 26.0 mL of base to neutralize a sample of your unknown acid solution. The pH of the solution was 7.82 when exactly 13 mL of base had been added, you notice that the concentration of the unknown acid was 0.1 M. What is the pKa of your unknown acid?

Answer:

The pK_a value is $pK_a =7.82$

Explanation:

From the question we are told

The volume of base is $V_B = 26.mL = 0.0260L$

The pH of solution is $pH = 7.82$

The concentration of the acid is $C_A = 0.1M$

From the pH we can see that the titration is between a strong base and a weak acid

Let assume that the the volume of acid is $V_A = 18mL= 0.018L$

Generally the concentration of base

$C_B = \frac{C_AV_A}{C_B}$

Substituting value

$C_B = \frac{0.1 * 0.01800}{0.0260}$

$C_B= 0.0692M$

When 13mL of the base is added a buffer is formed

The chemical equation of the reaction is

$HA_{(aq)} + OH^-_{(aq)} --------> A^{+}_{(aq)} + H_2 O_{(l)}$

Now before the reaction the number of mole of base is

$No \ of \ moles[N_B] = C_B * V_B$

Substituting value

$N_B = 0.01300 * 0.0692$

$= 0.0009 \ moles$

Now before the reaction the number of mole of acid is

$No \ of \ moles = C_B * V_B$

Substituting value

$N_A = 0.01800 *0.1$

$= 0.001800 \ moles$

Now after the reaction the number of moles of base is zero i.e has been used up

this mathematically represented as

$N_B ' = N_B - N_B = 0$

The number of moles of acid is

$N_A ' = N_A - N_B$

$= 0.0009\ moles$

The pH of this reaction can be mathematically represented as

$pH = pK_a + log \frac{[base]}{[acid]}$

Substituting values

$7.82 = pK_a +log \frac{0.0009}{0.0009}$

$pK_a =7.82$

8 0

3 years ago

HELP PLEASEEEEEEEEEEEEEEEEEE I CANT GO CANRVIL IF I CANT PASS THIS THEY WANNA SEE MY GRADES AND THIS WILL HELP ME GET MY GRADES

Daniel [21]

Answer:

3,3453 thank me later

Explanation:

1,3433

4 0

3 years ago

What is the empirical formula of a compound containing 90 grams carbon, 11 grams hydrogen, and 35 grams nitrogen? (5 points)

konstantin123 [22]

C3 H4 N1 ~~that’s what I think

8 0

3 years ago

Which group of human life cycle stages is in the correct order

zysi [14]

Answer:

foetus, baby, child, adolescent, adult and old person

Explanation:

eeet eez wut eeet eez

8 0

3 years ago