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3 years ago

Question 2(Multiple Choice Worth 4 points)

Chemistry

2 answers:

densk [106]3 years ago

6 0

Answer:

B. Construct a hypothesis

julsineya [31]3 years ago

6 0

Answer:

The correct answer will be option-C.

Explanation:

A scientific method is the systematic approach to understand and explain the natural events and phenomenon.

The method begins with making the observations which could lead to the formation of a scientific question. Background research is done based on which a predicted hypothesis is proposed which could be tested through the scientific experiments.

In the given question, student makes an observation on the basis of which he formulate a question. He do not review the background research on the question and directly formulates the hypothesis and follow other steps.

Since his method lacks the background research therefore, option-C is the correct answer.

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ASAP :))

grigory [225]

Answer:

Explanation:

Exergonic reactions are also called spontaneous reactions, because they can occur without the addition of energy. ... In this case, the products, or final state, have more free energy than the reactants, or initial state. Endergonic reactions are non-spontaneous, meaning that energy must be added before they can proceed.

5 0

3 years ago

A gas mixture being used to simulate the atmosphere of another planet at 23°c consists of 337 mg of methane, 148 mg of argon, an

Karolina [17]

The total pressure of the mixture is 65.5 kPa.

According to Dalton's Law of Partial Pressure,

The partial pressure of gas = Mole fraction of gas × Total pressure

Total Pressure = Sum of all the gases partial pressures

The number of moles of methane is,

$Moles \: of \: methane \: (16 g/mol) = 337 \: mg \times \frac{1 g}{1000 mg} \times \frac{ 1 mol}{16 g }$

= 0.021 mols

The moles of methane are 0.021 mols.

The number of moles of the argon,

$Moles \: of \: argon (40 g/mol) = 148 \: mg \times \frac{ 1 g}{1000 mg } \times \frac{ 1 mol}{40 g}$

= 0.003 mols

The number of moles of argon is 0.003 mols.

The number of moles of nitrogen is,

$Moles \: of \: nitrogen (28 g/mol) = 296 \: mg \times \frac{ 1 g}{1000 mg} \times \frac{ 1 mol/}{28 g}$

= 0.010 mols

The number of moles of nitrogen is 0.010 mols.

The total number of moles is,

= 0.021 + 0.003 + 0.010

= 0.034 mols

$Mole \: fraction = \frac{ Moles \: of \: solute }{Total \: number \: of \: moles \: of \: soulte \: and \: solvent}$

$= \frac{ 0.010 }{ 0.034}$

= 0.29

$0.29 \: P _{total} = 19 \: kPa$

$P _{total} = \frac{ 19 \: kPa }{0.29}$

= 65.5 kPa

Therefore, the total pressure of the mixture is 65.5 kPa.

To know more about Dalton's law, refer to the below link:

brainly.com/question/14119417

#SPJ4

6 0

1 year ago

Cual es la relación de la temperatura y la solubilidad?

DanielleElmas [232]

Answer:

A medida que aumenta la temperatura de un líquido, la solubilidad de los gases en ese líquido disminuye. Podemos usar la Segunda Ley de la Termodinámica para explicar por qué. Calentar una solución de un gas permite que las partículas de gas se muevan más libremente entre la solución y la fase gaseosa. La Segunda Ley predice que cambiarán al estado más desordenado, más altamente disperso y, por lo tanto, más probablemente gaseoso.

Explanation:

8 0

3 years ago

Balance the following skeleton reaction and identify the oxidizing and reducing agents: Include the states of all reactants and

kompoz [17]

Answer:

a. 2NO₂ (g) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + H₂O (l)

b. i. NO₂⁻ is the oxidizing agent

ii. NO₃⁻ is the reducing agent.

Explanation:

a. Balance the following skeleton reaction

The reaction is

NO₂ (g) → NO₃⁻ (aq) + NO₂⁻ (aq)

The half reactions are

NO₂ (g) → NO₃⁻ (aq) (1) and

NO₂ (g) → NO₂⁻ (aq) (2)

We balance the number of oxygen atoms in equation(1) by adding one H₂O molecule to the left side.

So, NO₂ (g) + H₂O (l) → NO₃⁻ (aq)

We now add two hydrogen ions 2H⁺ on the right hand side to balance the number of hydrogen atoms

NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + 2H⁺ (aq)

The charge on the left hand side is zero while the total charge on the right hand side is -1 + 2 = +1. To balance the charge on both sides, we add one electron to the right hand side.

So, NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + 2H⁺ (aq) + e⁻ (4)

Since the number of atoms in equation two are balanced, we balance the charge since the charge on the left hand side is zero and that on the right hand side is -1. So, we add one electron to the left hand side.

So, NO₂ (g) + e⁻ → NO₂⁻ (aq) (5)

We now add equation (4) and (5)

So, NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + 2H⁺ (aq) + e⁻ (4)

+ NO₂ (g) + e⁻ → NO₂⁻ (aq) (5)

2NO₂ (g) + H₂O (l) + e⁻ → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H⁺ (aq) + e⁻ (4)

2NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H⁺ (aq)

We now add two hydroxide ions to both sides of the equation.

So, 2NO₂ (g) + H₂O (l) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H⁺ (aq) + 2OH⁻ (aq)

The hydrogen ion and the hydroxide ion become a water molecule

2NO₂ (g) + H₂O (l) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H₂O (l)

2NO₂ (g) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + H₂O (l)

So, the required reaction is

2NO₂ (g) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + H₂O (l)

b. Identify the oxidizing agent and reducing agent

Since the oxidation number of oxygen in NO₂ is -2. Since the oxidation number of NO₂ is zero, we let x be the oxidation number of N.

So, x + 2 × (oxidation number of oxygen) = 0

x + 2(-2) = 0

x - 4 = 0

x = 4

Since the oxidation number of oxygen in NO₂⁻ is -1. Since the oxidation number of NO₂⁻ is -1, we let x be the oxidation number of N.

So, x + 2 × (oxidation number of oxygen) = 0

x + 2(-2) = -1

x - 4 = -1

x = 4 - 1

x = 3

Also, the oxidation number of oxygen in NO₃⁻ is -1. Since the oxidation number of NO₃⁻ is -1, we let x be the oxidation number of N.

So, x + 2 × (oxidation number of oxygen) = -1

x + 3(-2) = -1

x - 6 = -1

x = 6 - 1

x = 5

i. The oxidizing agent

The oxidation number of N changes from +4 in NO₂ to +3 in NO₂⁻. So, Nitrogen is reduced and thus NO₂⁻ is the oxidizing agent

ii. The reducing agent

The oxidation number of N changes from +4 in NO₂ to +5 in NO₃⁻. So, Nitrogen is oxidized and thus and NO₃⁻ is the reducing agent.

3 0

3 years ago

An atom that has 13 protons and 15 neutrons is an isotope of the element

kondaur [170]

That would be the element aluminum.

5 0

3 years ago