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adoni [48]
2 years ago
10

The validity of scientific theories and laws depends on evidence. Which of the following statements of evidence supports a law r

ather than a theory?
Electrons orbit the nucleus of an atom within a certain radius.
DNA analysis reveals that a modern species is related to an extinct species.
Seafloor spreading occurs at a rate of three centimeters per year in the mid-Atlantic.
The amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction.

Chemistry
2 answers:
Ksju [112]2 years ago
4 0

Answer:

d the amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction

mr_godi [17]2 years ago
3 0

Answer:

D

Explanation:

i am doing the test rn and i found the answer in other places

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Write a balanced equation from each cell notation:(b) Fe(s) | Fe²⁺(aq) | NO₃⁻(aq) | NO(g) | Pt(s)
tatiyna

The balanced redox reaction is

3Fe + 2NO₃⁻+ 8H+ → 3Fe²⁺ + 2NO + 4H2O

<h3>What is Galvanic cell? </h3>

It is a device that is used for the conversion of the chemical energy which is produce in the redox reaction into the electrical energy. It is also termed as the voltaic cell or electrochemical cell.

In the voltaic cell, at anode which is negative electrode of voltaic cell oxidation occurs and at the cathode which is positive electrode, reduction occurs

<h3>What is redox reaction? </h3>

The reaction in which both reduction and oxidation reaction takes place simultaneously is known as redox reaction.

<h3>What is oxidation reaction? </h3>

The reaction in which a substance or compound or species looses its electrons. In this reaction, oxidation state of an element increases.

<h3>What is reduction reaction? </h3>

The reaction in which a substance or compound or species accept the electrons. In this reaction, oxidation state of an element decreases.

The given two-half reactions are:

At anode:

3Fe → 3Fe²⁺ + 6e-

At cathode:

8H(+) + 2NO₃⁻ → 2NO + 4H2O

Redox reaction:

3Fe + 2NO₃⁻+ 8H+ → 3Fe²⁺ + 2NO + 4H2O

According to the voltaic cell, the half-cell reaction (1) shows oxidation reaction therefore, it occurs at anode and the half-cell reaction (2) shows reduction reaction therefore, it occurs at cathode.

Thus, we concluded that the redox reaction is

3Fe + 2NO₃⁻+ 8H+ → 3Fe²⁺ + 2NO + 4H2O

learn more about voltaic cell:

brainly.com/question/4052514

#SPJ4

7 0
1 year ago
I NEED HELPPPPPP ASAPPPPPPPPPPPP
Mama L [17]
I can’t read ? This what does it say
7 0
2 years ago
A solute is a strong electrolyte that ionizes into 2 ions. What is the molar mass of this solute if 30.76 grams added to exactly
Whitepunk [10]

Answer:

34.9 g/mol is the molar mass for this solute

Explanation:

Formula for boiling point elevation: ΔT = Kb . m . i

ΔT = Temperatures 's difference between pure solvent and solution → 0.899°C

Kb = Ebullioscopic constant → 0.511°C/m

m = molality (moles of solute/1kg of solvent)

i = 2 → The solute is a strong electrolyte that ionizes into 2 ions

For example: AB ⇒ A⁺  +  B⁻

Let's replace → 0.899°C = 0.511 °C/m . m . 2

0.899°C / 0.511 m/°C . 2 = m → 0.879 molal

This moles corresponds to 1 kg of solvent. Let's determine the molar mass

Molar mass (g/mol) → 30.76 g / 0.879 mol = 34.9 g/mol

4 0
3 years ago
You are asked to go into the lab and prepare an acetic acid - sodium acetate buffer solution with a ph of 4.00  0.02. what mola
Oxana [17]
Hello!

To solve this problem we are going to use the Henderson-Hasselbach equation and clear for the molar ratio. Keep in mind that we need the value for Acetic Acid's pKa, which can be found in tables and is 4,76:

 pH=pKa + log ( \frac{[CH_3COONa]}{[CH_3COOH]} )

\frac{[CH_3COOH]}{[CH_3COONa}= 10^{(pH-pKa)^{-1}}=10^{(4-4,76)^{-1}}=5,75

So, the mole ratio of CH₃COOH to CH₃COONa is 5,75

Have a nice day!

5 0
3 years ago
D.new
Lapatulllka [165]
I think the answer is B
4 0
2 years ago
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