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Stella [2.4K]
3 years ago
12

A 5.0-gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. Which combination of

these samples has the fastest reaction rate?
(1) a zinc strip and 1.0 M HCl(aq)
(2) a zinc strip and 3.0 M HCl(aq)
(3) zinc powder and 1.0 M HCl(aq)
(4) zinc powder and 3.0 M HCl(aq)
Chemistry
2 answers:
Radda [10]3 years ago
7 0
The answer is Zine powder and 3.0 M HCl (aq)
inessss [21]3 years ago
5 0

Answer:

(4) zinc powder and 3.0 M HCl(aq)

Explanation:

First consider the equation of reaction:

Zn + 2HCl --> ZnCl_2 + H_2

1 mole of Zinc requires 2 moles of HCl for reaction.

mole of zinc = mass/molar mass = 5.0/65.38 = 0.0765 mole

0.0765 mole of zinc will require: 0.0765 x 2 = 0.1530 mole HCl

Mole of 1.0 M HCl = Molarity x volume = 1 x 0.05 = 0.05 mole

Mole of 3.0 M HCl = 3 x 0.05 = 0.15

Hence, the 3.0 M HCl is what will give the required number of mole.

<em>Zinc in powder form will react faster compared to in strip because the former has higher surface area for reaction.</em>

Therefore, zinc powder and 3.0 M HCl will give the fastest reaction rate.

<em>The correct option is option 4.</em>

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Radda [10]

Answer is: activation energy of this reaction is 212,01975 kJ/mol.<span>
Arrhenius equation: ln(k</span>₁/k₂) = Ea/R (1/T₂ - 1/T₁).<span>
k</span>₁ = 0,000643 1/s.<span>
k</span>₂ = 0,00828 1/s.

T₁ = 622 K.

T₂ = 666 K.

R = 8,3145 J/Kmol.

<span> 1/T</span>₁ = 1/622 K = 0,0016 1/K.<span>
1/T</span>₂ = 1/666 K = 0,0015 1/K.<span>
ln(0,000643/0,00828) = Ea/8,3145 J/Kmol · (-0,0001 1/K).
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6 0
3 years ago
How many formula units are in 5.33 moles of cucl2​
Blizzard [7]

Answer:

32.1 × 10²³ formula units of CuCl₂

Explanation:

Given data:

Number of moles of CuCl₂ = 5.33 mol

Number of formula units  of CuCl₂ = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

one mole of  any substance contain 6.022 × 10²³ formula units thus,

5.33 moles of CuCl₂ = 5.33 ×6.022 × 10²³ formula units

32.1 × 10²³ formula units of CuCl₂

3 0
3 years ago
A 0.055 mol sample of formaldehyde vapor, CH2O, was placed in a heated 500 mL vessel and some of it decomposed. The reaction is
Elis [28]

Answer:

Kc for this reaction is 0.06825

Explanation:

Step 1: Data given

Number of moles formaldehyde CH2O = 0.055 moles

Volume = 500 mL = 0.500 L

At equilibrium, the CH2O(g) concentration = 0.051 mol

Step 2: The balanced equation

CH2O  <=>  H2 + CO

Step 3: Calculate the initial concentrations

Concentration = moles / volume

[CH2O] = 0.055 moles . 0.500 L

[CH2O] = 0.11 M

[H2] = 0M

[CO] = 0M

Step 4: The concentration at the equilibrium

[CH2O] = 0.11 - X M = 0.051 M

[H2] = XM

[CO] = XM

[CH2O] = 0.11 - X M = 0.051 M

X = 0.11 - 0.051 = 0.059

[H2] = XM = 0.059 M

[CO] = XM = 0.059 M

Step 5: Calculate Kc

Kc = [H2][CO]/[CHO]

Kc = (0.059 * 0.059) / 0.051

Kc = 0.06825

Kc for this reaction is 0.06825

7 0
3 years ago
How many chlorine atoms in 3ZnCl2
disa [49]

Answer:

6 Cl atoms

Explanation:

In one molecule of ZnCl2, we have 2 atoms of Cl

Therefore, in 3 molecules of ZnCl2, we'll have 3(2) atoms of Cl = 6 atoms of Cl.

please mark brainliest

6 0
3 years ago
Which of these are physical changes in matter chech all that apply
serious [3.7K]

Answer:

a pencil being sharpened

freezing water

boiling water

Explanation:

a physical change doesn't change the chemical structure of an object. That is why the other 2 are wrong

6 0
3 years ago
Read 2 more answers
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