What is required to make a fire? Is it exothermic or endothermic?

Answers

Answer 1

Answer:

Combustion as an Exothermic Reaction

Explanation:

When substances burn, they usually give off energy as heat and light. The combustion of wood is an exothermic reaction that releases a lot of energy as heat and light.

Answer 2

Answer:

Exothermic

Explanation:

because exothermic causes fires while endothermic doesn't


Related Questions

How many moles are in 3.4*10²⁶ molecules of H2O?​

Answers

Answer:

564.5027395 moles

Explanation.

a mole is 6.023×1023

(3.4×10^26)÷(6.023×10^23)= 564.5027395

Un convertidor catalítico acelera la reacción del monóxido de carbono con oxígeno para producir dióxido de carbono. ¿De qué manera cada uno de los siguientes cambios afectaría la velocidad de reacción que se muestra aquí? Sustente 2CO (g) + O2(g) → 2CO2(g) a). Quitar el catalizador. B). Eliminar parte de O2(g)

Answers

Answer:

a. Disminuye.

b. Disminuye.

Explanation:

¡Hola!

En este caso, considerando que tenemos una reacción en la cual se podría asumir que tanto la concentración de monóxido de carbono y la de oxígeno contribuye a la velocidad de reacción, de acuerdo a la siguiente cinética elemental:

[tex]r=k[CO]^2[O_2][/tex]

Al aplicar los siguientes cambios, resultaría:

a. En este caso, bien sabemos que la velocidad de reacción es aumentada al adicionar un catalizador ya que la constante de velocidad aumenta al disminuir la energía de activación; no obstante, al retirar el catalizador, la energía de activación aumentaría y por consiguiente la velocidad de reacción disminuiría.

b. En este caso, dado que la relación entre el oxígeno y la rapidez de reacción es directamente proporcional, es possible para nosotros determinar que al eliminar parte del oxígeno, la concentración disminuye y por ende la velocidad de reacción también.

¡Saludos!

The temperature of 335 g of water changed from 24.5oC to 26.4oC. How much heat did this sample absorb? C for water = 4.18 J/goC

Answers

Answer: The sample absorbed 3061.565J

Explanation:

Given that  

Mass of water  = 335g

Initial temperature  = 24.5°C

Final temperature = 26.4°C

Heat  absorbed by the sample is given as  = mass x specific heat of water x  temperature change

Heat  absorbed,q=mCΔt

The specific heat of water,C  = 4.81J/g°C

 

Therefore,  Heat absorbed,q  = 335 x 4.81h x (26.4  - 24.5)  = 3061.565J

Answer:

2660.57 J

Explanation:

26.4 - 24.5 = 1.9

335 x 4.18 x 1.9 = 2660.57 J

That is the correct answer.

Texas hill country is largely composed of soft limestone rock. When exposed to carbonic acid in rainwater, limestone can deteriorate and weaken. What affect does this process have on the landforms of Texas hill country?

Answers

Answer:

The answer is "It leads to the formation of underground caves"

Explanation:

Texas Hill Land is popular for its rolling hills, good wine, and authentic food. Its Texas Hill Property appeal is no mystery, recognized as being one of the top vacation destinations in the World. Texas Hill Structure is primarily mostly of weak calcareous stone. Calcium may worsen or degrade if exposed to carbon dioxide in rainwater. This practice affects the land of the Texas smoky Mountains leading to the formation of underwater groves.

If you can solve these thank you I will mark brainly.ASAP

Answers

Answer:Number 2 might be the second one

Explanation:

1. A substance with a definite mass but no definite volume or shape is a gas. Gas particles are spread far apart from one another, and they are constantly in motion such that they will fill up any container that they’re in. So the correct answer for 1 would be the first answer choice.

2. A liquid has a definite mass (all of the common states of matter have definite mass) and it has a definite volume: The particles of a given mass of liquid will occupy the same amount of space regardless of the shape of the liquid’s container; it likewise follows that a liquid does not have a definite shape. So, while one liter of water can fill and take the “shape” of a bowl or a bottle, there will always be one liter of water in each. So, the correct answer here would be the fourth answer choice.

3. A solid has a definite mass, a definite shape, and a definite volume precisely because its particles are not free to zip around freely (or rapidly). So the fourth statement is not true, and thus the fourth answer choice would be the correct answer here.

When hydrogen peroxide (H2O2) is used in rocket fuel, it produces water and oxygen (O2): Can someone help with parts B and C?

Answers

Answer:

Explanation: A foam forms when bubbles of a gas are trapped in a liquid or solid. In this case oxygen is generated when hydrogen peroxide breaks down into oxygen and water on contact with catalase, an enzyme found in liver. Enzymes are special protein molecules that speed up chemical reactions.

The shoes are green, a size 8, have white laces, made out of cotton, and have a rubber sole. The description given is a list of ___________ properities of the shoes. Question 33 options:
chemical
mechanical
physical
structural

Answers

Answer:

Physical i think, because it says, "The shoes are green, made of cotton, and rubber sole" everything in the passage described a physical property

Explanation:

tell me if im wrong, good luck

Answer:

physical

Explanation:

its listing a size 8, which eliminates chemical and mechanical. Also it lists their green, which eliminates structural, leaving physical left

A helium balloon with a volume of 5.0 L and a pressure of 105 kPa at 25°C floats up high in the sky where the pressure is 850 mm Hg and the temperature is -15°C. What is the new volume of the balloon?

Answers

Answer:

volume 2-     4.011 L

Now that you have exercised, walked your
jackalope, made cookies, and had juice, you
decide on a nap. Your body uses melatonin to
tell your brain and body that it's ready to sleep
or nap. Melatonin has the chemical formula
C13H16N2O2. The amount in your body at any
time is very small - less than 10 milligrams
(0.01 g)! Convert the melatonin to moles so
you can rest

Answers

Answer: The moles of melatonin are 0.000043

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]

Given mass of melatonin = 0.01 g

Molar mass of melatonin [tex](C_{13}H_{16}N_2O_2)[/tex] = 232.28 g/mol

[tex]\text{Number of moles of melatonin}=\frac{0.01 g}{232.28g/mol}=0.000043mol[/tex]

Thus the moles of melatonin in 0.01 g are 0.000043

2 H2 (g) + O2 (g) --> 2 H2O (l)

How many moles of hydrogen gas do you need to make 2 moles of liquid water?

Answers

Answer:

2H2(g]+O2(g]→2H2O(l]]. Notice that the reaction requires 2 moles of hydrogen gas and 1

Explanation:

Define Evaporation.
Thanks​

Answers

Answer:

evapouration is a type of vaporization that occur on the surface of liquid as it change into the gas phase.

hope it helps.

Evaporation happens when a liquid turns into a gas. It can be easily visualized when rain puddles “disappear” on a hot day or when wet clothes dry in the sun.

A gas system has an initial number of moles of 0.693 moles with the volume unknown. When the number of moles changes to 0.928 moles volume is found to be 7.98 L. What was the initial volume in mL?

Answers

Answer:

The initial volume in mL is 5959.2 mL

Explanation:

As the number of moles of a gas increases, the volume also increases.  Hence, number of moles and volumes are directly proportional i.e

n ∝ V

Where n is the number of moles and V is the volume

Then, n = cV

c is the proportionality constant

∴n/V = c

Hence n₁/V₁ = n₂/V₂

Where n₁ is the initial number of moles

V₁ is the initial volume

n₂ is the final number of moles

and V₂ is the final volume.

From the question,

n₁ = 0.693 moles

V₁ = ?

n₂ = 0.928 moles

V₂ = 7.98 L

Putting the values into the equation

n₁/V₁ = n₂/V₂

0.693 / V₁ = 0.928 / 7.98

Cross multiply

∴ 0.928V₁ = 0.693 × 7.98  

0.928V₁ = 5.53014

V₁ = 5.53014/0.928

V₁ = 5.9592 L

To convert to mL, multiply by 1000

∴ V₁ = 5.9592 × 1000 mL

V₁ = 5959.2 mL

Hence, the initial volume in mL is 5959.2 mL

A photon of visible light can be emitted when
Select one:
O a. an excited electron jumps down to ground state
O b. a ground state electron absorbs energy
O c. a ground state electron jumps to a higher energy level

Answers

Answer:

a ground state electron jumps to a higher energy level

gas
LA of certain mass occupies a volume of 650 cm3 under
a pressure of 760mmHg. Calculate the pressure under which
the volume of the
gas
cent
of its original volume
will be reduced by 10 per​

Answers

Answer:

844.4cm³

Explanation:

Using Boyle's law equation;

P1V1 = P2V2

Where;

P1 = initial pressure (mmHg)

P2 = final pressure (mmHg)

V1 = initial volume (cm³)

V2 = final volume (cm³)

According to the information in this question,

V1 = 650cm³

P1 = 760mmHg

P2 = ?

V2 = 10% reduction of V1

10% of 650 = 10/100 × 650

65

V2 = 650 - 65 = 585cm³

Using P1V1 = P2V2

P2 = P1V1 ÷ V2

P2 = (760 × 650) ÷ 585

P2 = 494000 ÷ 585

P2 = 844.44

final pressure (P2) = 844.4cm³

4Fe+3O2 →2Fe2O3

80.0 grams of iron are reacted with 50.0 grams of oxygen gas. Which of these reactants are the limiting reactant, and how many grams of iron (III) oxide would be produced?

Answers

Answer:

FFe

2

O

3

(

s

)

+

3

CO

(

g

)

2

Fe

(

s

)

+

3

CO

2

(

g

Explanation:

Question of the day

Seeds obtain their energy (food) directly from the soil as soon as they are planted.


True or False?

Answers

Answer:

false

Explanation:

it gets nourishment from the storage tissues in the seeds, when it develops into a young plant with roots, then it takes nutrients from the soil

False

When a seed is planted, it gets nourishment from the storage tissues in the seeds. The storage tissues could be in the cotyledon, peristem or endosperm. The storage tissue contain carbohydrates proteins,and fats content. When the embryo develops into a young plant with young roots, the plant then draws nutrients from the soil.

A box slides with an initial speed of 4.0 towards a spring on a frictionless horizontal surface. When the box
S
N
hits a spring with spring constant k = 150 the spring compresses by 0.30 m.
m
m
M
What is the mass of the box?

Answers

Answer: .84kg

Explanation:

Khan academy

A box slides with an initial speed of 4.0 kg m/s towards a spring on a frictionless horizontal surface. When the box hits a spring with spring constant k = 150 N/m, the spring compresses by 0.30 m.

What is the mass of the box?

Answer: 0.54 kg


5 Which two elements are combined in magnesium oxide?

Answers

Answer:

magnesium and oxygen

Explanation:

Which on is right O& Mg?
OMG
MgO
Mg2O2
Mg+2O-2

Answers

Answer:

MgO

is the correct answer

hope it helps

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Describe the kinds of potential energy that are stored by a car driving on a hill.

Answers

Answer:

The internal combustion engine in the car converts the potential chemical energy in gasoline and oxygen into thermal energy which is transformed into the mechanical energy that accelerates the vehicle (increasing its kinetic energy) by causing the pressure and performing the work on the pistons.

Explanation:

An electric car has a mass of 2,000 kg. the engine is producing a force of 3,500 N to move the vehicle forward,but it must overcome air friction equal to 500 N
What is the acceleration of the electric car m/s2?
record your answer and fill in below

Answers

Answer:

1.5 m/s²

Explanation:

From the diagram,

F-F' = ma............... Equation 1

Where F = Forward force of the vehicle, F' = Frictional force, m = mass of the electric car, a = acceleration of the car.

make a the subject of the equation

a = (F-F')/m........... Equation2

Given: F = 3500 N, F' = 500 N, m = 2000 kg

Substitute into equation 2

a = (3500-500)/2000

a = 3000/2000

a = 1.5 m/s²

How many moles are in 564 grams of copper

Answers

Answer:The answer is 63.546.

Explanation: The answer is 63.546. We assume you are converting between grams Copper and mole. You can view more details on each measurement unit: molecular weight of Copper or mol. The molecular formula for Copper is Cu. The SI base unit for amount of substance is the mole. 1 grams Copper is equal to 0.015736631731344 mole

Answer:

5.64 of copper

Explanation:

Given: 564 grams of copper

To find: in copper

Solution: If 1 grams Copper = 0.01 mole,

Then, 564 grams = multiply 564 and 0.01 mole

564 × 0.01 = 5.64

Therefore, there are 5.64 of copper in 564 grams

How many grams of NaOH are produced from 2.1g of Na2O?
Na2O + H20 --> 2NaOH

Answers

Answer:

2.72g

Explanation:

The balanced equation of this reaction is given as follows:

Na2O + H20 --> 2NaOH

Based on this balanced equation, 1 mole of Na2O will produce 2 moles of NaOH.

First, we need to convert mass of Na2O into moles by using the formula;

mole = mass/molar mass

Molar mass of Na2O = 23(2) + 16

= 46 + 16

= 62g/mol

mole = 2.1g/62g/mol

mole of Na2O = 0.034mol

Hence, if 1 mole of Na2O will produce 2 moles of NaOH.

Then, 0.034mol of Na2O will produce (0.034 × 2) = 0.068mol of NaOH.

To convert mole of NaOH to mass, we use;

mole = mass/molar mass

Molar mass of NaOH = 23 + 16 + 1 = 40g/mol

0.068 = mass/40

mass of NaOH produced = 2.72g.

explain in 3 complete sentences

Answers

Answer:Air in high pressure systems moves in an anticlockwise direction (in the southern hemisphere), while air in low pressure systems moves in a clockwise direction due to the rotation of the Earth. At the surface of the Earth air flows from high pressure systems into low pressure systems.

Explanation:

Warm air rises, creating a low pressure zone; cool air sinks, creating a high pressure zone. Air that moves horizontally between high and low pressure zones makes wind.Smaller pressure systems create localized winds that affect the weather and climate of a local area.

When a mixture of iron powder and sulphur is heated it glows more brightly than that of iron filings and sulphur.Explain this observation

Answers

Answer:

I don't know

Explanation:

mixture of iron powder and sulphur heated it glows because sulphur and iron are more reactive metals that they shine and sulphur can react with water produce fire it's write

For a reaction which change can increase the rates of reaction?

Answers

Answer:

temperature!!!

Explanation:

Reactant concentration, the physical state of the reactants, and surface area, temperature, and the presence of a catalyst are the four main factors that affect reaction rate.

What type of ionic compound is CO3?

Answers

Answer:

Carbon Trioxide

Explanation:

Its a Carbonite Ion which is also known as a polyatomic ion

Which statement is true about the particles of a liquid when the liquid changes into a solid?
They move closer to each other.
Their kinetic energy increases.
They stop vibrating.
The attractive force between them decreases.

Answers

Answer:

they move closer to each other

Answer:

They move closer to each other

Explanation:

Got it right on the test

Hope this helps :)

Does anyone know the simplest way to find the rate constant in rate law chemistry?

Answers

Answer:no I don’t sorry

Explanation:

How is evaporation related to molarity?

Answers

Answer:

Molarity is the amount (in mole) of solute in a solvent. If the solute is very volatile, then it will evaporated from the solution as temperature rising. So the amount of solute is decreasing, causing the molarity decreasing. If the solvent itself volatile, then the molarity will increase.

(Looked up the answer for you)

The relationship between evaporation and molarity is; the rate of evaporation of will decrease as the molarity increases

What is evaporation and molarity?

Molarity (M) is defined as the amount of a substance in a certain volume of solution. Molarity can also be defined as the number of moles of a solute per liters of a solution.

Now, the rate of evaporation of will decrease as the solute concentration increases due to the fact that for the same surface area for evaporation, as the concentration of the solute increases, less water molecules will get exposed to escape from the water surface.

Read more about Evaporation and Molarity at; https://brainly.com/question/14718840

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