Question:

1. Using the balanced equation, answer the following questions:

nalin [4]

Answer:

a) 2.53 × 10²³ molecules of O₂

b) 31.90 g of KCl

Explanation:

The balance chemical equation for given decomposition reaction is as follow;

2 KClO₃ → 2 KCl + 3 O₂

Step 1: <u>Calculate Moles for given amount of KClO₃;</u>

Moles = Mass / M.Mass

Moles = 34.35 g / 122.55 g/mol

Moles = 0.280 moles of KClO₃

Step 2: <u>Find out moles of O₂ produced;</u>

According to eq,

2 moles of KClO₃ produces = 3 moles of O₂

So,

0.280 moles of KClO₃ will produce = X moles of O₂

Solving for X,

X = 0.280 mol × 3 mol / 2 mol

X = 0.42 moles of O₂

Step 3: <u>Calculate No. of Molecules of O₂ as,</u>

No. of Molecules = Moles × 6.022 × 10²³

No. of Molecules = 0.42 mol × 6.022 × 10²³ molecules/mol

No. of Molecules = 2.53 × 10²³ molecules of O₂

Step 1: <u>Calculate Moles for given amount of KClO₃;</u>

Moles = Mass / M.Mass

Moles = 52.53 g / 122.55 g/mol

Moles = 0.428 moles of KClO₃

Step 2: <u>Find out moles of KCl produced;</u>

According to eq,

2 moles of KClO₃ produces = 2 moles of KCl

So,

0.428 moles of KClO₃ will produce = X moles of KCl

Solving for X,

X = 0.428 mol × 2 mol / 2 mol

X = 0.428 moles of KCl

Step 3: <u>Calculate Mass of KCl as;</u>

Mass = Moles × M.Mass

Mass = 0.428 mol × 74.55 g/mol

Mass = 31.90 g of KCl

6 0

2 years ago

How many moles of salt will you be using in this recipe?

user100 [1]

5 molessss booo booo

6 0

2 years ago

What is the energy of a wave with wavelength of 4.2 x 10-7 m. (Hint: Calculate for frequency first.)

erik [133]

Answer:

Option B. 4.74×10¯¹⁹ J.

Explanation:

The following data were obtained from the question:

Wavelength (λ) = 4.2×10¯⁷ m

Energy (E) =.?

Next, we shall determine the frequency of the wave. This can be obtained as follow:

Wavelength (λ) = 4.2×10¯⁷ m

Velocity (v) = constant = 3×10⁸ m/s

Frequency (f) =.?

v = λf

3×10⁸ = 4.2×10¯⁷ × f

Divide both side by 4.2×10¯⁷

f = 3×10⁸ / 4.2×10¯⁷

f = 7.143×10¹⁴ s¯¹

Therefore, the frequency of the wave is 7.143×10¹⁴ s¯¹.

Finally, we shall determine the energy of the wave using the following formula

E = hf

Where

E is the energy.

h is the Planck's constant

f is the frequency

Thus, the enery of the wave can be obtained as follow:

Frequency (f) = 7.143×10¹⁴ s¯¹.

Planck's constant = 6.63×10¯³⁴ Js

Energy (E) =..?

E = hf

E = 6.63×10¯³⁴ × 7.14×10¹⁴

E = 4.74×10¯¹⁹ J

Therefore, the energy of the wave is 4.74×10¯¹⁹ J.

5 0

3 years ago

Aluminum has a face-centered cubic unit cell. How many atoms of Al are present in each unit cell

Serjik [45]

Answer:4

Explanation:

As shown in the image attached, a face-centred cubic structure has 8 atoms at the corners and 6 face center atoms.

Each corner atom contributes to eight cell, so per unit cell 1/8 ×8 =1atom

Face center atoms contributes to two unit cells 1/2 × 6=3atoms

Total atoms =3+1=4atoms

Therefore the atoms in Al FCC per unit cell is 4

7 0

3 years ago

Using the following reaction:

Romashka-Z-Leto [24]

Answer:

Mn is the oxidizing agent.

N is the reducing agent.

Explanation:

Hello!

In this case, according to the undergoing chemical reaction, it is seen that the manganese in KMnO4 has an oxidation state of 7+, in MnSO4 of 2+ and nitrogen in KNO2 is 3+ and in KNO3 is 5+; thus we have the following half-reactions:

$Mn^{7+}+5e^-\rightarrow Mn^{2+}\\\\N^{3+}\rightarrow N^{5+}+2e^-$

Thus, since manganese is undergoing a decrease in the oxidation state, we infer it is the oxidizing agent whereas nitrogen, undergoing an increase in the oxidation state is the reducing agent.

Best regards!

5 0

2 years ago