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3 years ago

An atom has a mass number of 24 and 13 neutrons. What is the atomic number of this atom? Express

1 answer:

8 0

A=mass number (protons + neutrons)
Z=atomic number (protons)
N=number of neutrons.

A=Z+N

Data:
A=24
N=13

Therefore:
24=Z+13
Z=24-13=11

Answer: The atomic number of this atom is 11. (The element is sodium)

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A reaction mechanism has the following elementary step as the slow step: B2A What is the rate law for this elementary step? O ra

xenn [34]

Answer:

r = k [ B ]

Explanation:

B → 2A

⇒ r = k [ A ]/2 = k [ B ]

3 0

3 years ago

3. Given 20g of Barium Hydroxide, how many grams of

anastassius [24]

The number of grams of ammonium nitrate (NH₄NO₃) it would take for all the barium hydroxide to react is 18.7g

First, we will write the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

Ba(OH)₂ + 2NH₄NO₃ → 2NH₄OH + Ba(NO₃)₂

This means, 1 mole of barium hydroxide is required to react with 2 moles of ammonium nitrate

Now, we will calculate the number of moles of barium hydroxide present.

Mass of barium hydroxide (Ba(OH)₂) = 20 g

Using the formula

$Number\ of\ moles = \frac{Mass}{Molar\ mass}$

Molar mass of Ba(OH)₂ = 171.34 g/mol

∴ Number of moles of Ba(OH)₂ present = $\frac{20}{171.34}$

Number of moles of Ba(OH)₂ present = 0.116727 mole

Now,

Since 1 mole of barium hydroxide is required to react with 2 moles of ammonium nitrate

Then,

0.116727 mole of barium hydroxide will react with 2 × 0.116727 mole of ammonium nitrate

2 × 0.116727 = 0.233454 mole

∴ Number of moles of NH₄NO₃ required is 0.233454 mole

Now, for the mass of ammonium nitrate (NH₄NO₃) required

From the formula

Mass = Number of moles × Molar mass

Molar mass of NH₄NO₃ = 80.043 g/mol

∴ Mass of NH₄NO₃ required = 0.233454 × 80.043

Mass of NH₄NO₃ required = 18.68636 g

Mass of NH₄NO₃ required ≅ 18.7g

Hence, the number of grams of ammonium nitrate (NH₄NO₃) it would take for all the barium hydroxide to react is 18.7g

Learn more on determining mass of reactant required here: brainly.com/question/11232389

6 0

2 years ago

A lake in rural maine drops in ph from 7 to 5 as a result of acid rain falling into it. how has the h+ ion concentration change

Jlenok [28]

The H+ concentration in the lake has increased as a result of the acid rain.
The original pH of the lake was 7, which mean the water is neutral, but due to the acid rain, it drops to 5. This means, that the water has become acidic and how have more hydrogen ion. The H+ concentration in the lake has 100 times compares with its original pH.

3 0

3 years ago

Peut-on être exact sans être précis?

Evgesh-ka [11]

Answer:

I think you can.

8 0

2 years ago

Find the amount of heat energy needed to convert 400 grams of ice at -38°C to steam at 160°C.

Marianna [84]

The amount of heat energy needed to convert 400 g of ice at -38 °C to steam at 160 °C is 1.28×10⁶ J (Option D)

<h3>How to determine the heat required change the temperature from –38 °C to 0 °C </h3>

Mass (M) = 400 g = 400 / 1000 = 0.4 Kg
Initial temperature (T₁) = –25 °C
Final temperature (T₂) = 0 °
Change in temperature (ΔT) = 0 – (–38) = 38 °C
Specific heat capacity (C) = 2050 J/(kg·°C)
Heat (Q₁) =?

Q = MCΔT

Q₁ = 0.4 × 2050 × 38

Q₁ = 31160 J

<h3>How to determine the heat required to melt the ice at 0 °C</h3>

Mass (m) = 0.4 Kg
Latent heat of fusion (L) = 334 KJ/Kg = 334 × 1000 = 334000 J/Kg
Heat (Q₂) =?

Q = mL

Q₂ = 0.4 × 334000

Q₂ = 133600 J

<h3>How to determine the heat required to change the temperature from 0 °C to 100 °C </h3>

Mass (M) = 0.4 Kg
Initial temperature (T₁) = 0 °C
Final temperature (T₂) = 100 °C
Change in temperature (ΔT) = 100 – 0 = 100 °C
Specific heat capacity (C) = 4180 J/(kg·°C)
Heat (Q₃) =?

Q = MCΔT

Q₃ = 0.4 × 4180 × 100

Q₃ = 167200 J

<h3>How to determine the heat required to vaporize the water at 100 °C</h3>

Mass (m) = 0.4 Kg
Latent heat of vaporisation (Hv) = 2260 KJ/Kg = 2260 × 1000 = 2260000 J/Kg
Heat (Q₄) =?

Q = mHv

Q₄ = 0.4 × 2260000

Q₄ = 904000 J

<h3>How to determine the heat required to change the temperature from 100 °C to 160 °C </h3>

Mass (M) = 0.4 Kg
Initial temperature (T₁) = 100 °C
Final temperature (T₂) = 160 °C
Change in temperature (ΔT) = 160 – 100 = 60 °C
Specific heat capacity (C) = 1996 J/(kg·°C)
Heat (Q₅) =?

Q = MCΔT

Q₅ = 0.4 × 1996 × 60

Q₅ = 47904 J

<h3>How to determine the heat required to change the temperature from –38 °C to 160 °C</h3>

Heat for –38 °C to 0°C (Q₁) = 31160 J
Heat for melting (Q₂) = 133600 J
Heat for 0 °C to 100 °C (Q₃) = 167200 J
Heat for vaporization (Q₄) = 904000 J
Heat for 100 °C to 160 °C (Q₅) = 47904 J
Heat for –38 °C to 160 °C (Qₜ) =?

Qₜ = Q₁ + Q₂ + Q₃ + Q₄ + Q₅

Qₜ = 31160 + 133600 + 167200 + 904000 + 47904

Qₜ = 1.28×10⁶ J

Learn more about heat transfer:

brainly.com/question/10286596

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7 0

2 years ago