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3 years ago

Which option correctly describes the enthalpy of formation?

Chemistry

1 answer:

leonid [27]3 years ago

4 0

Answer: Endothermic reaction.

Explanation: A chemical reaction in which energy is absorbed from the surrounding environment.

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if three oxygen particles are needed to form ozone, how many units of ozone could be formed from 6 oxygen particles? from 9? fro

tensa zangetsu [6.8K]

<h3>Answers:</h3>

1) 2 Units of Ozone

2) 3 Units of Ozone

3) 9 Units of Ozone

<h3>Solution:</h3>

1) From 6 Oxygen Particles;

As given,

3 Oxygen Particles form = 1 Unit of Ozone

So,

6 Oxygen Particles will form = X Units of Ozone

Solving for X,

X = (6 O Particles × 1 Unit of Ozone) ÷ 3 O Particles

X = 2 Units of Ozone

2) From 9 Oxygen Particles;

As given,

3 Oxygen Particles form = 1 Unit of Ozone

So,

9 Oxygen Particles will form = X Units of Ozone

Solving for X,

X = (9 O Particles × 1 Unit of Ozone) ÷ 3 O Particles

X = 3 Units of Ozone

3) From 27 Oxygen Particles;

As given,

3 Oxygen Particles form = 1 Unit of Ozone

So,

27 Oxygen Particles will form = X Units of Ozone

Solving for X,

X = (27 O Particles × 1 Unit of Ozone) ÷ 3 O Particles

X = 9 Units of Ozone

3 0

3 years ago

What is the volume of 0.640 grams of Oz gas at Standard Temperature and Pressure (STP)?

Ilia_Sergeevich [38]

Answer: The volume of 0.640 grams of $O_{2}$ gas at Standard Temperature and Pressure (STP) is 0.449 L.

Explanation:

Given: Mass of $O_{2}$ gas = 0.640 g

Pressure = 1.0 atm

Temperature = 273 K

As number of moles is the mass of substance divided by its molar mass.

So, moles of $O_{2}$ (molar mass = 32.0 g/mol) is as follows.

$No. of moles = \frac{mass}{molar mass}\\= \frac{0.640 g}{32.0 g/mol}\\= 0.02 mol$

Now, ideal gas equation is used to calculate the volume as follows.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

$PV = nRT\\1.0 atm \times V = 0.02 mol \times 0.0821 L atm/mol K \times 273 K\\V = 0.449 L$

Thus, we can conclude that the volume of 0.640 grams of $O_{2}$ gas at Standard Temperature and Pressure (STP) is 0.449 L.

6 0

3 years ago

If a buffer solution is 0.130 M in a weak acid (K_a = 1.7 x 10^-5) and 0.590 M in its conjugate base, what is the pH?

Serggg [28]

Use the Henderson-Hasselbach equation:
pH = pKa + log[base]/[acid]
pH = -log(1.7 x 10^-5) + log(0.590/0.130) = 5.43

8 0

3 years ago

While in Europe, if you drive 109 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per lite

MrRissso [65]

Answer:

The amount is $x = 113.3 \ dollars$

Explanation:

From the question we are told that

The distance traveled per day is $l = 109\ km = \frac{109}{1.609} = 67.74 \ mi$

The cost of one liter is $c = 1.10 \ euros/liter = 1.10 * 1.26 = 1.36 \ dollars/liter$

The car's gas mileage is $b = 22.0 \ mi/gal$

Generally the amount of distance covered in one week is evaluated as

$z = 67.74 * 7$

$z = 474.18 \ mi$

The amount of gas used in one week by the car is mathematically represented as

$k = \frac{ z}{ b}$

=> $k = \frac{ 474.18}{ 22}$

=> $k = 22 \ gal$

converting to liters

$k = 22 * 3.78541=83.28 \ liters$

Thus the amount spent on gas in one week is

$x = k * c$

=> $x = 83.28 * 1.36$

=> $x = 113.3 \ dollars$

5 0

3 years ago

Water clings to the side of a graduated cylinder because of what property?

Amiraneli [1.4K]

I think its cohesion because it has a magnetic like effect that <span> - and + effects within the water molecule will want to stick to any other objects and because everything its composed of electrons and protons, so they connect with +,-,+,-,+,-,+,-,+,-,</span>

5 0

3 years ago