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Sophie [7]
3 years ago
8

Express (158 lb)2 to three significant figures with appropriate units

Chemistry
2 answers:
statuscvo [17]3 years ago
5 0
(158lb)2 = 158 lb * 158 lb 
This gives us 24964 lb^2 
To solve the solution to 3sf we obtain 25000 lb^2. 
Hence 25000 to 3sf
Setler [38]3 years ago
5 0

Answer: 2.50 × 10⁴


Justification:


1) The expression is: (158 lbs)²


2) When two amounts are multiplied, the product must be shown with the same number of significant figures of that of the factor with the least number of significant figures.


3) So you have to muliply 158 by itself (square) and then round to 3 significant figures.


4) The number 158 has 3 significan figures, so the product shall show also 3 significant figures:


(158 lb)² = 158 lb × 158 lb = 24,964 lb², which must be rounded to 3 significant figures: 25,000.


Since, the fourth figure was greater than 5, the third signficant figure must be increased. Since the third signficant figure is 9, the increase is translated to the second significant figure.


5) Now, to indicate tha the number of significan figures is 3, you have to use scientific notation:


25,000 = 2.50 × 10³, where the 3 signficant figures are 2, 5, and 0.

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Which of these pairs indicates an incorrect coupling of reversible reactions?dehydration synthesis and hydrolysisanabolic and ca
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Answer:

option C= hydrolysis and break down

Explanation:

All other three pairs are correct coupling of each others.

Option A= dehydration synthesis and hydrolysis

Dehydration synthesis:

In dehydration synthesis monomers combine through the covalent bonds and form large molecules. The large molecules are called polymers. The water as a byproduct also released when monomers joints together.

Hydrolysis:

In hydrolysis the polymers are break down into monomers by using water molecules. The catalysts are also required in this process.

Option B= Catabolic and Anabolic

Anabolic:

In this process smaller molecules combine to gather to form large complex molecules by using energy.

For example simple glucose molecules join together to form large disaccharides.

Catabolic:

It is the break down of large complex molecules to the smaller molecules.

For example during cellular respiration sugar molecules break down and generate energy.

Option D=  Break down and synthesis

The break down and synthesis are also reverse pair of each others. The  synthesis involve the formation of molecules form smaller component while the break down involve destruction of molecules into smaller units.

8 0
3 years ago
Democritius thought that
andre [41]
Atoms because electrons, neutrons and protons are in a atom
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Mamont248 [21]
The answer is Heat energy moves from warmer objects to cooler ones
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What mass, in grams, of CO2 and H20 N<br> is formed from 2.55 mol of propane?
Black_prince [1.1K]

Answer: The mass of CO_2 and H_2O produced are 336.6 g and 183.6 g respectively.

Explanation:

The combustion reaction between propane and oxygen leads to formation of carbon dioxide and water.

Law of Conservation of mass states that the mass will remain constant for a balanced equation. This is carried out when the total number of atoms on reactant side is same as the total number of atoms on the product side. Thus the equation must be balanced.

C_3H_8+5O_2\rightarrow 3CO_2+4H_2O

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mass of CO_2=moles\times {\text {molar mass}}=7.65mol\times 44g/mol=336.6g

b) 1 mol of propane produces = 4 moles of H_2O

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