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inna [77]
3 years ago
15

Which of these statements is correct about how the first forms of life appeared on Earth?

Chemistry
2 answers:
lara31 [8.8K]3 years ago
6 0

the answer to your question would be A


hope i heled

Greeley [361]3 years ago
4 0

Answer:

A.  Non-living molecules evolved into living molecules by chemical changes.

Explanation:

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The average propane cylinder for a residential grill holds approximately 18 kg of propane. how much energy (in kj) is released b
Angelina_Jolie [31]
Let's begin with the basic values  that will be used in the solution.

The formula of propane is C3H8. It is an alkane, a hydrocarbon with the general formula of CnH2n+2. Notice that hydrocarbons have only Carbon and Hydrogen atoms. Its molar mass (M) is 44 g.

Molar Mass Calculation is done as like that
C=12 g/mol, H=1 g/mol. 1 mole propane has 3 moles Carbon atoms and 8 mole Hydrogen atoms. M(
C3H8)= 3*12+ 8*1= 44 g

Combustion reaction of hydrocarbons gives carbon dioxide and water by releasing energy. That energy is called as enthalpy of combustion (
ΔHc°).  

ΔHc° of propane equals -2202.0 kj/mol. Burning of 1 mole C3H8 releases 2202 kj energy. Minus sign only indicates that the energy is given out ( an exothermic reaction ).

Let's write the combustion reaction.
C3H8 + O2 ---> CO2 + H20 (unbalanced) 
ΔHc° = -2202 kj/mol

Now, we calculate mole of 20 kg propane. Convert kilogram into gram since we use molar mass is defined in grams.
mole=mass/molar mass ; n=m/M ; n= 20000 g /44 (g/mol)=454 mole

1 mole propane releases 2202 kj energy.
454 mole propane release 2202 kj *454= 1000909 kj

The answer is 1000909 kj.



6 0
4 years ago
What are the characteristics of Mercury? (Select all that apply.)
Sunny_sXe [5.5K]

Answer:

less gravity, closest to the sun

5 0
3 years ago
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What is the function of the nervous system? What is the basic unit of the nervous system?
s2008m [1.1K]

Answer:

basic unit of le nervous system is ur nerves brother nah im jp ur brain bcs if u didnt have a brain u wouldnt feel anything :D

Explanation:

3 0
2 years ago
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Which of the following processes does not facilitate containment?
Marta_Voda [28]

Enrichment of uranium-235 is done. Hence, option A is correct.

<h3>What is the meaning of containment?</h3>

The act, process, or means of keeping something within limits the containment of health costs.

Enrichment is a process of increasing the proportion of fissile isotope found in uranium ore (represented by the symbol 'U') to make it usable as nuclear fuel or the compressed, explosive core of nuclear weapons.

Hence, option A is correct.

Learn more about containment here:

brainly.com/question/3299455

#SPJ1

7 0
2 years ago
Answer question 13. What is the mechanical advantage of a lever that can lift a 100 N load with a input force of 20 N
vazorg [7]
MA= output force/ input force
MA= 100N/20N
MA= 50
8 0
3 years ago
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