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3 years ago

Which one is a chemical reaction? Why?

Chemistry

1 answer:

Alex17521 [72]3 years ago

3 0

Answer:

Copper turns green on exposure to air

Explanation:

Liquid water freezes to form ice: Physical change

Reason: Water can melt back when it becomes ice.

Copper turns green on exposure to air: Chemical change

Reason: The copper can not change back from the green state when it turns green.

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What two forces act in the nucleus to create a 'nuclear tug-of-war'?

Alex787 [66]

Answer:

Electrostatic repulsion, strong nuclear force

Explanation:

The nucleus consists of protons and neutrons. protons are positively charged while neutrons possess no charge.

Since protons are positively charged, they repel each other strongly (like charges repel). This strong repulsion of like charges makes the nucleus somewhat unstable leading to spontaneous fission of heavy nuclei.

However, an opposing force called nuclear attractive force tends to hold the nucleons together. This attraction occurs when two nucleons are bonded by a particle called a π meson.

Hence, the two forces that act in the nucleus to create a 'nuclear tug-of-war' are electrostatic repulsion and a strong nuclear force.

5 0

3 years ago

25 POINTS! Will mark brainliest if you have a good response!

Zolol [24]

Electrons uniting with electrons of another atom is the cause in this relationship. The effect is a chemical change.

6 0

3 years ago

A 50.0 mL sample of 12.0 M HCl is diluted to 200 mL. What is true about the diluted solution?

kobusy [5.1K]

The concentration of the solution reduces and the number of moles of solute isn't affected.

Data;

V1 = 50mL
C1 = 12.0M
V2 = 200mL
C2 = ?

<h3>Facts about the diluted solution</h3>

1. When the solution is diluted, the concentration changes and this time, the concentration reduces.

Using dilution formula

$c_1 v_1 = c_2 v_2\\12 * 50 = c_2 * 200\\c_2 = \frac{600}{200} \\c_2 = 3M$

The concentration of the solution reduces.

2. The number of moles remains the same.

When a solution is diluted, the number of moles remains the same because there's no change in the mass of the solute.

Learn more on concentration of a solution here;

brainly.com/question/2201903

7 0

3 years ago

CH4 + O2 → CO2 + H2O

Scilla [17]

Answer:

9.8 × 10²⁴ molecules H₂O

General Formulas and Concepts:

Atomic Structure

Reading a Periodic Table
Moles
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Organic

Naming carbons

Stoichiometry

Analyzing reaction rxn
Using Dimensional Analysis

Explanation:

Step 1: Define

[RxN - Unbalanced] CH₄ + O₂ → CO₂ + H₂O

[RxN - Balanced] CH₄ + 2O₂ → CO₂ + 2H₂O

[Given] 130 g CH₄

Step 2: Identify Conversions

Avogadro's Number

[RxN] 1 mol CH₄ → 2 mol H₂O

[PT] Molar Mass of C: 12.01 g/mol

[PT] Molar Mass of H: 1.01 g/mol

Molar Mass of CH₄: 12.01 + 4(1.01) = 16.05 g/mol

Step 3: Stoichiometry

[DA] Set up conversion: $\displaystyle 130 \ g \ CH_4(\frac{1 \ mol \ CH_4}{16.05 \ g \ CH_4})(\frac{2 \ mol \ H_2O}{1 \ mol \ CH_4})(\frac{6.022 \cdot 10^{23} \ molecules \ H_2O}{1 \ mol \ H_2O})$
[DA] Divide/Multiply [Cancel out units]: $\displaystyle 9.75526 \cdot 10^{24} \ molecules \ H_2O$

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

9.75526 × 10²⁴ molecules H₂O ≈ 9.8 × 10²⁴ molecules H₂O

8 0

3 years ago

The equations ? It’s for a chemistry class, and he said we need to explain and write down the math problems?

alina1380 [7]

Answer:

I think this is because math and chemistry go together and the math problems are science related.

Explanation:

3 0

2 years ago