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Tema [17]
4 years ago
12

Prehistory can be described as _____.

Chemistry
1 answer:
Furkat [3]4 years ago
8 0
Prehistory is the time before history.

History is usually defined as the time in the past BEFORE written (or similar) solid evidence, for which we can only infer what happened.

So the correct answer is C.
You might be interested in
What are the relative ion concentrations in an acid solution?
Veronika [31]
Answer is: more H⁺ ions than OH⁻ ions.
<span>An Arrhenius acid is a substance that dissociates in water to form hydrogen ions or protons. 
For example, hydrochloric acid dissociate in aqueous solution to form hydrogen ions (H</span>⁺) and chloride anion (Cl⁻):<span>
HCl(aq) → H</span>⁺(aq) + Cl⁻<span>(aq).
</span>

An Arrhenius base is a substance that dissociates in water to form hydroxide ions (OH⁻<span>). 
For example lithium hydroxide is an Arrhenius base:</span>

LiOH(aq) → Li⁺(aq) + OH⁻(aq).


4 0
3 years ago
A one or two letter abbreviation for a chemical element. True or false
Feliz [49]

Answer:

True

Explanation:

All the chemical elements have their abbreviations as one or two letters

The first letter in the abbreviation is a capital letter and the second letter is always a small letter

Majority of abbreviations are based on their english names

3 0
3 years ago
To determine the enthalpy and entropy of dissolving a compound, you need to measure the Ksp at multiple _______. Then, plot ln(K
Aloiza [94]

Answer:

To determine the enthalpy and entropy of dissolving a compound, you need to measure the Ksp at multiple temperatures. Then, plot ln(Ksp) vs. 1/T. The slope of the plotted line relates to the enthalpy (ΔH) of dissolving and the intercept of the plotted line relates to the entropy (ΔS) of dissolving.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us use the thermodynamic definition of the Gibbs free energy and its relationship with Ksp as follows:

\Delta G=-RTln(Ksp)\\\\\Delta G=\Delta H-T\Delta S

Thus, by combining them, we obtain:

-RTln(Ksp)=\Delta H-T\Delta S\\\\ln(Ksp)=-\frac{\Delta H}{RT} +\frac{T\Delta S}{RT} \\\\ln(Ksp)=-\frac{\Delta H}{RT} +\frac{\Delta S}{R}

Which is related to the general line equation:

y=mx+b

Whereas:

y=ln(Ksp)\\\\m=-\frac{\Delta H}{R} \\\\x=\frac{1}{T} \\\\b=\frac{\Delta S}{R}

It means that we answer to the blanks as follows:

To determine the enthalpy and entropy of dissolving a compound, you need to measure the Ksp at multiple temperatures. Then, plot ln(Ksp) vs. 1/T. The slope of the plotted line relates to the enthalpy (ΔH) of dissolving and the intercept of the plotted line relates to the entropy (ΔS) of dissolving.

Regards!

8 0
3 years ago
Help please!!!!
frez [133]
It is either D or B

Hope I helped


8 0
3 years ago
I will give brainiest! PLEASE ANSWER ASAP.How does the law of conservation of mass apply to this reaction: C2H4 + 3O2 → 2H2O + 2
blondinia [14]
<h3>Answer:</h3>

The law of conservation of mass has already been applied. There is an equal number of each element on both sides of the equation.

<h3>Explanation:</h3>

<u>We are given;</u>

  • The equation;

C₂H₄ + 3O₂ → 2H₂O + 2CO₂

We need to ask ourselves the following questions;

Is the equation balanced?

  • Yes, the equation because the number of atoms of each element is equal on both sides of the equation.
  • That is; Reactants: 2 carbon atoms, 4 hydrogen atoms and 6 oxygen atoms.
  • Products: 2 carbon atoms, 4 hydrogen atoms and 6 oxygen

What is the law of conservation of mass?

  • According to the law of conservation of mass, the mass of reactants should always be equal to the mass of the products in chemical reactions.

What makes the equation obey the law of conservation of mass?

  • For an equation to obey the law of conservation of mass, it must be balanced.
  • In this case, <u>the equation given is already balanced and therefore obeys the law of conservation of mass</u>.
7 0
4 years ago
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