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3 years ago

6

1. The diagram models the forces acting on a box. 2N 2N- Box - 2 N 5 N Which of the following best describes the motion of the b

ox?

1 answer:

zhenek [66]3 years ago

6 0

Answer: The box is moving downward with increasing speed.

Explanation:

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Of the following gases, ______ will have the greatest rate of effusion at a given temperature.A) NH3B) CH4C) ArD) HBrE) HCl

s344n2d4d5 [400]

Answer:

CH₄

Explanation:

According to Graham's law, <em>the rate of effusion of a gas (r) is inversely proportional to the square root of its molar mass (M)</em>.

Let's consider the following gases and their molar masses.

A) NH₃ 17.03 g/mol

B) CH₄ 16.04 g/mol

C) Ar 39.95 g/mol

D) HBr 80.91 g/mol

E) HCl 36.46 g/mol

Of these gases, CH₄ will have the greatest rate of effusion at a given temperature because it has the lowest molar mass.

7 0

2 years ago

The average kinetic energy of a sample of water molecules is –

ycow [4]

Answer:

c. increased as the temperature is increased

Explanation:

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2 years ago

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What do you know about plants cell and animal cells?<br> restate the answer and answer it

Marta_Voda [28]

Explanation:

Plant cells have a cell wall, as well as a cell membrane. In plants, the cell wall surrounds the cell membrane. This gives the plant cell its unique rectangular shape. Animal cells simply have a cell membrane, but no cell wall.

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2 years ago

Benzene would react_____________.

Vlada [557]

Answer: Benzene is less reactive than methylbenzoate and more reactive than Nitrobenzene

Explanation:

This is because the methyl group on the benzene ring is an electron donating group leading to the activation of the ring and subsequently leading to more canonical resonance structure at the intermediate stage of the reaction enhancing the faster reactivity

However for the Nitrobenzene the nitro group is an electron withdrawing group leading to a slower activation and less resonance canonical structure at the reaction intermediate leading to a slower reaction than the reaction of benzene without the nitro group

4 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

2 years ago