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3 years ago

How could the survivors about starting a fire?

Chemistry

1 answer:

joja [24]3 years ago

6 0

Answer:

The ancient Greeks believed that fire was one the four basic elements that composed all things in the universe. In the mythology of virtually every culture, fire is a sacred substance that gives life or power. Fire is not, in fact, a substance. When you gaze at the leaping flames of a campfire, you’re observing not an object, but a process – a chemical reaction. It’s the same chemical reaction that occurs when a cut apple left on the counter turns brown, when silver tarnishes or when an iron nail rusts.

That process is oxidation: combining oxygen with another substance. The defining difference between a fire and your half-eaten apple is speed: fire is an oxidation process that happens very fast, so that light, heat and sound are released — often with enough force and majesty to justify the ancients’ reverence.The sudden release of energy causes temperatures to rise, sometimes by thousands of degrees. And it also results in smoke, the toxic waste of fire’s leftovers.

The fire triangle and the fire tetrahedron

Fire TetrahedronThe fire triangle identifies the three needed components of fire:

fuel (something that will burn)

heat (enough to make the fuel burn)

and air (oxygen)

Explanation: i hope this helps sry its long

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If 35.0 mL of water in a graduated cylinder is displaced by 8.00 mL

sdas [7]

Answer:

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume}\\$

From the question

volume = final volume of water - initial volume of water

volume = 35 - 8 = 27 mL

We have

$density = \frac{14}{27} \\ = 0.518518...$

We have the final answer as

Hope this helps you

3 0

2 years ago

Acetic acid has a pKa of 4.74. Buffer A: 0.10 M HC2H3O2, 0.10 M NaC2H3O2 Buffer B: 0.30 M HC2H3O2, 0.30 M NaC2H3O2 Buffer C: 0.5

e-lub [12.9K]

Answer:

Buffer B has the highest buffer capacity.

Buffer C has the lowest buffer capacity.

Explanation:

An effective weak acid-conjugate base buffer should have pH equal to $pK_{a}$ of the weak acid. For buffers with the same pH, higher the concentrations of the components in a buffer, higher will the buffer capacity.

Acetic acid is a weak acid and $CH_{3}COO^{-}$ is the conjugate base So, all the given buffers are weak acid-conjugate base buffers. The pH of these buffers are expressed as (Henderson-Hasselbalch):

$pH=pK_{a}(CH_{3}COOH)+log\frac{[CH_{3}COO^{-}]}{[CH_{3}COOH]}$

$pK_{a}(CH_{3}COOH)=4.74$

Buffer A: $pH=4.74+log(\frac{0.10}{0.10})=4.74$

Buffer B: $pH=4.74+log(\frac{0.30}{0.30})=4.74$

Buffer C: $pH=4.74+log(\frac{0.10}{0.50})=4.04$

So, both buffer A and buffer B has same pH value which is also equal to $pK_{a}$ . Buffer B has higher concentrations of the components as compared to buffer A, Hence, buffer B has the highest buffer capacity.

The pH of buffer C is far away from $pK_{a}$ . Therefore, buffer C has the lowest buffer capacity.

6 0

2 years ago

Define natural gas, liquefied petroleum gas (LPG), and liquefied natural gas (LNG). What three countries have most of the world’

mrs_skeptik [129]

Answer:

The answer is treated below.

Explanation:

Natural gas: Natural gas is not used in its pure form; it is processed and converted into cleaner fuel for consumption. It is a fossil fuel composed almost entirely of methane, but contain small amounts of other gases, including ethane, propane, pentane and butane. It is a combustible, gaseous mixture of simple hydrocarbon compounds, usually found in deep underground reservoirs formed by porous rock. Natural gas is mainly used as fuel for generating heat and electricity.

Liquefied petroleum gas (LPG): Liquefied Petroleum Gas is a byproduct of natural gas and oil extraction and crude oil refining . At room temperature, liquefied petroleum gas is a colourless and odourless gas which consists generally of butane (C4H10) or propane (C3H8) or a mixture of both.

Liquefied natural gas (LNG): Is natural gas that has been liquefied for ease of transport or storage. It is refrigerated to a very low temperature (-162 Celsius). At this temperature it becomes an odourless, non-toxic liquid that can be safely transported over long distances.

Three countries that have most of the world’s natural gas reserves

Russia
Iran
Qatar

Major advantages of using conventional natural gas as an energy resource:

It is less expensive when compared to other fossil fuels.
It is safer and easier to store when compared to other fossil fuels

Major disadvantages of using conventional natural gas as an energy resource:

It costs more to recover the remaining natural gas because of flow, access, etc.
It is not a renewable source.
it is a combustible material, It must be handled with care.
It does not contribute to greenhouse gases.

Three sources of unconventional natural gas :

Tight Gas
Shale Gas
Coalbed Methane

Major problems related to the use of Tight Gas

When Hydrofluoric acid is used to release tight gas in reserves it potentially an issue simply because the substance is so dangerous. A spill or a leak could harm workers and pollute groundwater for uses.

Major problems related to the use of Shale Gas

Risk of ground and surface water contamination.
Have impacts on air quality.

Major problems related to the use of Coalbed Methane

The development of coalbed methane will result to soil disturbance from construction of wells, roads, and the associated pipeline and electric power rights-of-ways.
It has impact on wildlife.

8 0

3 years ago

Calculate the number of molecules in 46.0 grams of water

Natalka [10]

Answer:

Explanation:

Since water has a chemical formula of H2O , there will be 2 moles of hydrogen in every mole of water. In one mole of water, there will exist approximately 6.02⋅1023 water molecules.

4 0

3 years ago

The rate constant for this second‑order reaction is 0.610 M − 1 ⋅ s − 1 0.610 M−1⋅s−1 at 300 ∘ C. 300 ∘C. A ⟶ products A⟶product

Darya [45]

Answer: It takes 3.120 seconds for the concentration of A to decrease from 0.860 M to 0.260 M.

Explanation:

Integrated rate law for second order kinetics is given by:

$\frac{1}{a}=kt+\frac{1}{a_0}$