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SpyIntel [72]
3 years ago
7

Mass and energy are conserved Question 13 options: A) only in chemical changes. B) always in physical changes and sometimes in c

hemical changes. C) only in physical changes. D) in chemical changes and physical changes.
Chemistry
1 answer:
Roman55 [17]3 years ago
3 0

Answer:

B

Explanation:

sometimes it can change chemically but not all the time.

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What is the volume of the rectangular prism below? A.38,832 mm3 B.480,000 mm3 C.499,200 mm3 D.501,120 mm3
Mkey [24]

Answer:

c.

Explanation:

8 0
3 years ago
How does burning affect an object's property? Burning can cause an object to increase in volume. Burning changes the chemical ma
Jobisdone [24]

Answer: Burning changes the chemical make up of an object.

Explanation:

A chemical change can be defined as a change in the substance when it combines with other kind of substance to form a new substance. A chemical change can also occur when a substance is broken down into two or more products. These changes cannot be reversed. These changes affect the physical make up of an object. For example, burning as when an object is burned it cannot be transformed into its original form. A wood if burned can be converted into ash, water and carbon dioxide cannot regain its original form after burning so burning brings about chemical change in an object.

3 0
3 years ago
The balanced equation for combustion in an acetylene torch is shown below: 2C2H2 + 5O2 → 4CO2 + 2H2O The acetylene tank contains
andriy [413]

Answer: 67.2 moles

Explanation: 2C_2H5+5O_2\rightarrow 4CO_2+2H_2O

According to the given balanced equation, 2 moles of acetylene C_2H_2 combine with 5 moles of oxygen O_2  to produce 4 moles of carbon dioxide CO_2.

Thus if 2 moles of acetylene C_2H_2 combine with = 5 moles of oxygen O_2

35 moles of acetylene C_2H_2 combine with=\frac{5}{2}\times {35}=87.5 moles of oxygen O_2

But as only 84 moles of oxygen are available, acetylene is not a limiting reagent.

5 moles of oxygen O_2 reacts with = 2 moles of acetylene C_2H_2

84 moles of oxygen O_2 reacts with=\frac{2}{5}\times {84}=33.6 moles of acetylene C_2H_2

Thus Oxygen is the limiting reagent as it limits the formation of products. Acetylene is excess reagent as it is present in excess.

2 moles of acetylene C_2H_2  produce= 4 moles of carbon dioxide CO_2.

33.6 moles of acetylene C_2H_2 produce=\frac{4}{2}\times {33.6}=67.2 moles of of carbon dioxide CO_2.


8 0
3 years ago
Read 2 more answers
How many grams of lithium sulfide (Li2S) are in 275 g of a 16 % aqueous solution of Li2S?
krok68 [10]

Answer:

600 mAh·g−1

Explanation:

i hope this is good let me know if its wrong

3 0
3 years ago
When a molecule of nad+ gains a hydrogen atom, the molecule becomes reduced.
Ilia_Sergeevich [38]
The answer is true.the molecule becomes reduced.
5 0
3 years ago
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