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Kobotan [32]
2 years ago
8

1. Burning a candle is a chemical change. What is the primary evidence that burning the candle is a chemical reaction?

Chemistry
1 answer:
tankabanditka [31]2 years ago
8 0
<h2>Answer 1) Option B) Temperature Change</h2><h3>Explanation : </h3>

The burning of candle is the reaction where both physical and chemical changes occurs. A physical change where the melted wax is cooled and the wax is obtained again. Whereas the chemical change takes place when the wick of the candle burns using the oxygen in the air and produces heat and light. So, this change in temperature is a chemical change as the burning process cannot be reverse, from the burnt  products like soot, smoke and carbon dioxide. Therefore, the temperature change is the evidence of a chemical change in the burning of candle.

<h2>Answer 2) Option B) It is a chemical change because heat energy is absorbed and the pack gets colder.</h2><h3>Explanation :</h3>

When Clara is mixing the vial contents the ice pack gets colder. On application of the ice pack on the injured area absorbs the heat from that region and becomes more colder. This happens because in the ice pack was the medium for the temperature change that was occurring. This temperature change by absorbing heat getting colder is the evidence of a chemical change.

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Mumz [18]

Eutrophication

In an aged aquatic habitat like a lake, eutrophication is the progressive rise in the concentration of phosphorus, nitrogen, and other plant nutrients. As the volume of organic matter that can be converted into nutrients increases, the productivity or fertility of such an ecosystem also naturally rises.

<h3>What is Eutrophication ?</h3>

Eutrophication may be caused by a number of things, including overuse of fertilisers, untreated sewage, the use of phosphorous-containing detergents, and industrial waste discharge.

  • Eutrophication naturally. Natural eutrophication is a process that develops in water resources over a very long period of time as a result of a slow buildup of nutrients and organic waste. Anthropogenic or cultural eutrophication.

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3 0
1 year ago
At a particular temperature, 12.0 moles of so3 is placed into a 3.0-l rigid container, and the so3 dissociates by the reaction 2
saul85 [17]
            2 SO₃ --> 2 SO₂ + O₂
I             12             0          0
C           -2x           +2x      +x
---------------------------------------------
E         12-2x          2x         x

Since the moles of SO₂ at equilibrium is 3 mol, 2x = 3. Then, x = 1.5 mol. So, the amounts at equilibrium is:
SO₃: 12 - 2(1.5) = 9
SO₂: 2(1.5) = 3
O₂: 1.5

The formula for K basing on the stoichiometric reaction is:
K = [SO₂]²[O₂]/[SO₃]² 
where the unit used is conc in mol/L.

K = [3 mol/3 L]²[1.5 mol/3 L]/[9 mol/3 L]²
<em>K = 0.0556</em>
4 0
3 years ago
Identify the blocks and groups of elements in the periodic table​
djyliett [7]

Explanation:

The periodic table is a table that arranges elements based on their atomic numbers into groups and periods.

The groups are the vertical arrangement of elements. All elements in a group share similar chemical properties because they have the same number of elements in their valence shell. The periodic table groups are:

               Group                             Other names

              1A or 1                               Alkali metals

              IIA or 2                              Alkaline earth metals

             IIIA or 3                            Boron family

             VIA or 6                             Chalcogens

            VIIA or 17                            Halogens

             O-18                                  Inert elements

             IIIB-IIB                              Transition elements

There are 18 vertical columns divided into 8 tall groups or main groups which are 1A to O. The short groups or subgroups are from numerals 1B to VIII.

The periodic table can be divided into four blocks based on the type of sublevels their valence electrons occupy.

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  • Group IIIA to O constitute the p-block
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  • The lanthanides and actinides makes up the f-block

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3 0
3 years ago
Why do the planets keep orbiting the sun
dsp73
There's no reason, it's just because the sun has a gravitational pull
3 0
3 years ago
Suppose that CaO is added as an impurity to Li2O. If the Ca2+ substitutes for Li+, what kind of vacancies would you expect to fo
Leno4ka [110]

Answer:

Positive charges are eliminated by creating lithium vacancies, and for every Ca2+ ion added, a single lithium vacancy is formed.

Explanation:

The addition of calcium oxide as an impurity to lithium oxide creates an  interstices due to the replacement of the Lithium ion by calcium ion. The creation of  interstices is as a result of  the replacement of the positive ions (Lithium by calcium). To make the reaction neutral, these replacements must occur  when the interstices are formed

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2 years ago
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