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3 years ago

How is energy involved in chemical and physical changes?

1 answer:

7 0

Chemical changes within matter always use energy; physical changes sometimes use energy, though they use much less energy than chemical changes. Physical changes use energy to change the physical state of a substance. Chemical changes either release or absorb energy when changing a substance into a completely new one.

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A home solar energy storage unit uses 4.75 ✕ 102 L of water for storing energy. On a sunny day, the water absorbed 2.75 ✕ 104 kJ

Sav [38]

Answer : The water's temperature change will be, $13.85^oC$

Explanation : Given,

Density of water = 0.998 g/mL

Volume of water = $4.75\times 10^2L=4.75\times 10^5mL$

(conversion used : 1 L = 1000 mL)

Specific heat of water = $4.184J/g^oC$

Heat absorbed = $2.75\times 10^4kJ=2.75\times 10^7J$

(conversion used : 1 kJ = 1000 J)

First we have to determine the mass of water.

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}$

$\text{Mass of water}=(0.998g/mL)\times (4.75\times 10^5mL)=474050g$

Now we have to calculate the change in temperature of water.

Formula used :

$Q=m\times C_w\times \Delta T$

where,

Q = heat absorbed by water

m = mass of water

$C_w$ = specific heat of water

$\Delta T$ = change in temperature

Now put all the given value in the above formula, we get:

$2.75\times 10^7J=474050g\times 4.184J/g^oC\times \Delta T$

$\Delta T=13.85^oC$

Therefore, the water's temperature change will be, $13.85^oC$

8 0

4 years ago

What is the chloride of berylium

Jobisdone [24]

It is a compound i hope i helped

3 0

4 years ago

If you grew a plant with labeled atoms of carbon, nitrogen, hydrogen, and oxygen, which of these sources would dominate the mass

Alborosie

Labeled carbon and oxygen, coming from carbon dioxide as source

Plants are autotrophs, which means that they capable of producing their own "food" from inorganic substances using energy from light or chemical reactions. Plants produce their food mainly by photosynthesis, which utilizes energy in the form of sunlight to convert carbon dioxide in the atmosphere to complex organic molecules as source of food.

4 0

4 years ago

Balance chemical equation hbr(aq)+o2(g) h20(l)+br2(l)

Oksanka [162]

4HBr(aq) + O2(g)= 2H2O(l) + 2Br2(l)

3 0

3 years ago

The line graph shows the heights of plants grown in fertilized and unfertilized soil. Based on this information, what will most

AfilCa [17]

Answer:

g) Neither plant should increase by 1 cm in height.

Explanation:

See the graph for this question on the figure attached.

The growing of the plant A is represented by the line that goes above the other. At start, that line has a slope that rises about 0.75 cm ( height increase) in 1 day. From the day 2 and forward the slope of the line decreases. The line reaches its highest point about at day 4 and seems to start decreasing. Thus, you should predict that on the day six it most likely does not increase in height.

The growing of the plant B is represented by the line drawn below the other. As for the plant B, the growing decreases with the number of days. Between the days 4 and 5 the line is almost flat, which means that most likely this plant will not grow on the day six or grow less than 0.5 cm.

Thus, for both plants you can say that on day six, most likley, neither should increase by 1 cm in height (option g).

4 0

3 years ago