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kirza4 [7]
3 years ago
12

When determining whether a chemical reaction has taken place you observe and look for several indicators. Which would be conside

red an indication that a chemical reaction or chemical change has taken place? es -) A) Solid melts. B) Heat is given off. Substance dissolves D) Substance changes shape. Physical Science​
Chemistry
1 answer:
Phoenix [80]3 years ago
4 0

Answer:

B) Heat is given off.

Explanation:

When heat is given off, a chemical change must have occurred and such a reaction is termed an exothermic reaction.

A chemical change is one in which;

  • the process is not easily reversible
  • leads to the production of new kinds of matter
  • involves change in mass
  • requires a considerable amount of energy.

Most chemical reactions are accompanied by heat changes.

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Dfine chemical reaction​
allsm [11]

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A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

Explanation:

Pretty much just not a physical reaction or otherwise

4 0
3 years ago
Which of the following statements correctly explains how latitude affects temperature?
dusya [7]

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It's 1, places that are closer to the equator receive more direct sunlight and have

Explanation:

7 0
2 years ago
How does the vegetation surface type affect the amount of runoff
maxonik [38]

Answer:

<em>The type of vegetation a surface does affect the </em><em>water coming from above to sink in or runoff. </em>

Explanation:

This is how the vegetation affects the runoff:-

The leaves and stems present in the vegetation do not let the water fall directly on the soil and makes the process rather slow which makes the water to get to the ground slowly and sink in properly inside the soil rather than running off.

If the vegetation present is dense with  there was being hairy then also the water would not run out and will get absorbed by the roots letting the soil intact

5 0
3 years ago
based on the article what are some of the advantages that can be given by radio frequency and microwaves​
bonufazy [111]

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higher data rates are

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6 0
3 years ago
Determine the limiting reactant (lr) and the mass (in g) of nitrogen that can be formed from 50.0 g n2o4 and 45.0 g n2h4. some p
Licemer1 [7]
                                                   N2O4(l) + 2 N2H4(l) → 3 N2(g) + 4 H2O(g)
1) to calculate the limiting reactant you need to pass grams to moles.
<span> moles is calculated by dividing mass by molar mass
</span>
mass of N2O4: 50.0 g 
molar mass of <span>N2O4 = 92.02 g/mol
</span><span>molar mass of N2H4 = 32.05 g/mol.
</span>mass of N2H4:45.0 g

moles N2O4=50.0/92.02 g/mol= 0,54 mol of N2O4
moles N2H4= 45/32.05 g/mol= 1,40 mol of <span><span>N2H4

</span> 2)</span>
By looking at the balanced equation, you can see that 1 mol of N2O4 needs 2 moles of N2H4 to fully react . So to react  0,54 moles of N2O4, you need 2x0,54 moles of <span>N2H4 moles
</span><span>N2H4 needed = 1,08 moles.
You have more that 1,08 moles </span><span>N2H4, so this means the limiting reagent is not N2H4, it's </span>N2O4. The molecule that has molecules that are left is never the limiting reactant.

3) 1 mol of N2O4 reacting, will produce 3 mol of N2 (look at the equation)
There are 0,54 mol of N2O4 available to react, so how many moles will produce of N2?
1 mol N2O4------------3 mol of N2
0,54 mol N2O4--------x
x=1,62 mol of N2

4) the only thing left to do is convert the moles obtained, to grams.
We use the same formula as before, moles equal to mass divided by molar mass.
moles= \frac{grams}{molar mass}             (molar mass of N2= 28)
1,62 mol of N2= mass/ 28
mass of N2= 45,36 grams

4 0
3 years ago
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