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andreev551 [17]
3 years ago
7

What causes an echo?

Chemistry
2 answers:
Ira Lisetskai [31]3 years ago
8 0
Answer:
Reflection

Reason:

Reflection is like looking at yourself through a mirror, so it would be the same for sound. And sound waves are REFLECTED back
spayn [35]3 years ago
7 0
The answer is reflection
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Organic compounds are distinguished by molecules that contain ________ bonded to other elements.
fredd [130]
The answer is carbon
6 0
3 years ago
When an apple or banana is cut, a chemical reaction with air causes the flesh to turn brown. Placing the fruit in a cold place,
PIT_PIT [208]

Apples turn brown when exposed to air because it undergoes aerial oxidation.  Due to this, when the inside of the apple is exposed to the air containing oxygen and water, it turns brown. When apple is uncut, skin of the apple protects it from this process. 


If the peeled apple in kept in the refrigerator, the oxidation reaction is greatly slowed down. This is because, rate of chemical reaction decreases with temperature. Hence, in refrigerator it would take several days for it to turn brown.

8 0
3 years ago
The freezing point of water in degrees Celsius is [ Select ] __________. The freezing point of water in degrees Fahrenheit is [
ElenaW [278]

Answer: 0, 32 , 273

Explanation:

The freezing point of water in degree Celsius, Fahrenheit and Kelvin are in the following order;   0  , 32  , 273

4 0
3 years ago
Calculate the volume of H2(g) at 273 K and 2.00 atm that will be formed when 275 mL of 0.725 M HCl solution reacts with excess M
Ksenya-84 [330]

Answer:

V=1.11L

Explanation:

Hello,

In this case, the chemical reaction is:

2HCl+Mg\rightarrow MgCl_2+H_2

Thus, the reacting moles of hydrochloric acid are computed with the volume of the given solution:

n_{HCl}=0.725\frac{mol}{L} *0.275L=0.199molHCl

Hence, we perform the proportional factors having the 2:1 molar relationship between hydrochloric acid and hydrogen to find the yielded moles of hydrogen:

n_{H_2}=0.199molHCl*\frac{1molH_2}{2molHCl} =0.0995molH_2

Finally, by using the ideal gas equation we obtain the volume for the specified conditions as shown below:

V=\frac{nRT}{P} =\frac{0.0995molH_2*0.082\frac{atm*L}{mol*K}*273K}{2.00atm} \\\\V=1.11L

Best regards.

4 0
3 years ago
Read 2 more answers
Very easy and only answer number 4 what word is supposed to be there
LekaFEV [45]

Answer:

chlorophyll

Explanation:

the chlorophyll in the leaf absorbs all the colors of the radiation from sun but reflects only green colour. that is why we see green when we look at a leaf on a tree.

3 0
3 years ago
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