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umka21 [38]
3 years ago
10

How to tell if an equation is exothermic or endothermic?

Chemistry
1 answer:
levacccp [35]3 years ago
3 0
The standard enthalpy change of a reaction is positive thus endothermic.

The standard enthalpy change of a reaction is negative thus exothermic.

Hope it helped!
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Water from a lake changes to a gas state in the process of what?
boyakko [2]
Of heating. Or when the lake is exposed to boil because of the temperature.
7 0
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The pH of a neutral solution is below 7 above 7 7 7.5
morpeh [17]
The pH scale ranges from 0 to 14 and goes from acidic to alkaline, where 7 - the center of the scale - is the most neutral.

Answer:
The pH of a neutral solution is exactly 7.
4 0
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Which law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of t
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How many moles of Al would be produced from 20 moles of Al2O3?<br> 2Al2O3<br> -&gt;<br> 4A1 + 302
Evgesh-ka [11]
<h3>Answer:</h3>

\displaystyle 40 \ mol \ Al

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
  • Left to Right<u> </u>

<u>Chemistry</u>

<u>Stoichiometry</u>

  • Using Dimensional Analysis
<h3>Explanation:</h3>

<u>Step 1: Define</u>

[RxN - Balanced] 2Al₂O₃ → 4Al + 3O₂

[Given] 20 mol Al₂O₃

<u>Step 2: Identify Conversions</u>

[RxN] 2 mol Al₂O₃ → 4 mol Al

<u>Step 3: Stoich</u>

  1. [DA] Set up:                                                                                                     \displaystyle 20 \ mol \ Al_2O_3(\frac{4 \ mol \ Al}{2 \ mol \ Al_2O_3})
  2. [DA] Multiply/Divide [Cancel out units]:                                                         \displaystyle 40 \ mol \ Al

<u>Step 4:Check</u>

<em>Follow sig fig rules and round. We are given 1 sig fig.</em>

Since our final answer already has 1 sig fig, there is no need to round.

4 0
2 years ago
Do nonmetals form anions or cations?
MrRa [10]
Since medals form cations
nonmedals form anions
8 0
3 years ago
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