How is an endothermic reaction identified?


A. It has a large heat capacity.
B. It gives off heat as a product.
C. It requires heat as a reactant.
O D. It results in a phase change.

Answers

Answer 1

Answer:

Endothermic is identified if the process requires heat as a reactant, since endothermic means "intake of heat", so it has to take in some type of heat.


Related Questions

When 11.2 liters of hydrogen gas is made by adding zinc to sulfuric acid, what mass
of zinc is needed?
Zn + H2SO4 -> H2 + ZnSO4

Answers

32.7 g Zn

Explanation:

First convert the amount of gas into moles:

11.2 L H2 × (1 mol H2/22.4 L H2) = 0.500 mol H2

Then use the molar ratio to find the amount of zinc necessary to produce the amount of gas above:

0.500 mol H2 × (1 mol Zn/1 mol H2)

= 0.500 mol Zn

Now use the molar mass of zinc to find the number of grams of zinc for the reaction to occur:

0.500 mol Zn × (65.38 g Zn/1 mol Zn)

= 32.7 g Zn

Which of the following is an example of nuclear fission?
A. A gamma emitter is used to trace movement of chemicals in the
environment.
B. A radioactive drug that emits electrons is used to treat cancer in a
patient.
O c. Two different isotopes of hydrogen form an isotope of helium on
the sun.
O D. A large radioactive atom breaks into smaller atoms, producing
nuclear energy.

Answers

The statement which is an example of nuclear fission is that a large radioactive atom breaks into smaller atoms, producing nuclear energy.

What is nuclear fission?

Nuclear fission is a kind of radioactive decay reaction in which an unstable nuclei of an atom will split into smaller stable nuclei by the emission of lots of energy.

Gamma emitter is used inside the human body to trace the information that assists in making a diagnosis by the help of medication.To treat cancer patient high energetic rays like x-rays, gamma-rays are used.Formation of isotope of helium from two different isotopes of hydrogen is an example of nuclear fussion reaction.

Hence in nuclear fission a large radioactive atom breaks into smaller atoms, producing nuclear energy.

To know more about nuclear fission, visit the below link:
https://brainly.com/question/3992688

. Calculate the pH and the pOH of each of the following solutions at 25 °C for which the substances ionize completely:
(a) 0.200 M HCl

(b) 0.0143 M NaOH

(c) 3.0 M HNO3

(d) 0.0031 M Ca(OH)2

Answers

a. HCl:
pH= -log [H3O+]
PH=-log (0.200)
= 0.699

poH= 14-0.699
= 13.301

b. NaOH:
PoH= -log [OH-]
= -log (0.0143)
= 1.845
pH= 14-poH
= 14- 1.845
= 12.16

c. HNO3:
PH= -log[H3O+]
=-log(3.0)
= -0.4771
poH= 14-pH
= 14-9-0.4771
= 14.4771

pH= -0.4771, poH= 14.4771

d. [Ca(OH)2] = 0.0031M
[OH-]= 2X0.0031
[OH-] = 0.0062M

PoH= - log[OH-]
=-log(0.0062)
=-log(6.2x10-3)
=-(-2.21)
= 2.21
PH=14-poH
=14-2.21
=11.79
POH=2.21, PH= 11.79

Based on the molarity of the solutions;

For 0.200 M HCl; pH = 0.699, pOH = 13.301For 0.0143 M NaOH; pOH = 1.845, pH = 12.16For 3.0 M HNO3; pH = -0.4771, poH = 14.4771For 0.0031 M Ca(OH)2; pOH = 2.21, pH = 11.79

What pHand pOH?

pH is the negative logarithm to base ten of the hydrogen ions concentration of a solution.

pH = -log[H+]

pOH is the negative logarithm to base ten of the hydroxide ions concentration.

pOH = -log[OH-]

Also;

pH + pOH = 14

For HCl:

pH = -log [H3O+]

pH =-log (0.200)

pH = 0.699

Then;

poH= 14-0.699

pOH = 13.301

For NaOH:

pOH= -log [OH-]

= -log (0.0143)

pOH = 1.845

Then;

pH= 14-poH

= 14- 1.845

pH = 12.16

For HNO3:

pH= -log[H3O+]

=-log(3.0)

= -0.4771

Then;

pOH = 14-9-0.4771

pOH = 14.4771

For [Ca(OH)2]

molarity = 0.0031M

2 moles of OH- are produced

[OH-]= 2 × 0.0031

[OH-] = 0.0062M

pOH = - log[OH-]

=-log(0.0062)

=-log(6.2x10-3)

=-(-2.21)

pOH = 2.21

Then;

pH =14-2.21

pH =11.79

Learn more about pH and pOH at: https://brainly.com/question/13557815

round 5,239 to 2 significant figures

Answers

Answer:

5240

Explanation:

I'm not sure tho sorry

28.0 g of N2 gas was found to occupy a volume of 8.44 L at a
pressure of 320 kPa. What is the temperature of the gas?

Answers

Are there options for this question? ...........

Answer:

Therefore, the temperature of the gas is 84.9 ℃. 28.0 g of N2 gas was found to occupy a volume of 8.44 L at a pressure of 320 kPa.

Explanation:

Therefore, the temperature of the gas is 84.9 ℃. 28.0 g of N2 gas was found to occupy a volume of 8.44 L at a pressure of 320 kPa.

Determine the number of subatomic particles in bromine-35.

Answers

Number of subatomic particles=35+36+35=106

Explanation:

Atomic number=35

Mass number=71

No. of proton p=35

No. of neutron n=71−35=36

No. of electron e=35

What force is important in the creation of both coal and petroleum?​

Answers

Explanation:

heat and pressure are two main forces that transform organic matter into fossil fuels

Q1.what is irragation​

Answers

Answer:

Irrigation is the artificial process of applying controlled amounts of water to land to assist in production of crops. Irrigation helps to grow agricultural crops, maintain landscapes, and revegetate disturbed soils in dry areas and during periods of less than average rainfall.

Answer: The watering of crop plants in regular intervals is known as irrigation. ... Weeds are unwanted plants thet grows with the crop plants. Weeding means to remove those plants. It is done manually or by machine. Using khurpi it is done manually and using seed drill it is done by machine.

Explanation:

Irrigation is the artificial application of water to the soil through various systems of tubes, pumps, and sprays. Irrigation is usually used in areas where rainfall is irregular or dry times or drought is expected.

Hope it helps

Please help I’ll give brainliest

Answers

REACTION TYPE:

Single displacement/Oxidation-reduction

(Hope this helped UwU)

Answer:

Synthesis reaction is the answer

Consider the following chemical reaction:
HF + NaOH - NaF + H20
Energy must be invested in order for the reaction to proceed.
What bonds must be broken in order for the reaction to proceed.
Select ALL that apply.
A. An ionic bond between sodium and hydroxide.
B. An ionic bond between sodium and fluorine.
C. A covalent bond between sodiume and fluorine.
D. An ionic bond between hydrogen and fluorine.
DE. A covalent bond between hydrogen and fluorine.
DE A covalent bond between hydrogen and oxygen

Answers

Answer: The correct options are A and E

Explanation:

A chemical reaction is defined as the reaction in which two or more chemical substances react to form two or more different chemical substances.

A new substance (product) is formed in a chemical reaction when the bonds between the reactants are broken so that the new bonds between the products can be formed.

For a given chemical reaction:

[tex]HF+NaOH\rightarrow NaF+H_2O[/tex]

Here,

HF is a covalent compound as sharing of electrons take place between hydrogen and fluorine atom

NaOH is an ionic compound as a complete transfer of electrons occurs from sodium to hydroxide.

Thus, to form the products, an ionic bond between sodium and hydroxide must be broken coupled with a covalent bond between hydrogen and fluorine.

Hence, the correct options are A and E

An element X has the proton number 18.
The next element in the periodic table is an element Y.
Which statement is correct?

Answers

Answer:

This question is incomplete

Explanation:

This question is incomplete. However, the element X with the atomic number of 18 is Argon (Ar) while the next element (element Y) in the periodic table, with atomic number 19, is potassium (K).

Element X is found in the group zero (also called group 18 and elements found therewith are referred to as noble gases) of the periodic table while element Y is found in group 1 (elements found here are referred to as alkali metals).

Element X has a completely filled outermost shell while element Y has one electron in its outermost shell.

Element X is a metal while element Y is a nonmetal.

Which value could be the y-coordinate for point Q?
215
42
2/13
8/2

Answers

I think the answer is the first choice

what is the chemical formula : hydrogen and chlorine ?

Answers

Answer:

HCl

Explanation:

HCl
That’s is the formula
I hope this helps

ASAP!!!!!!!!!!!!A marble bag contains 10 red marbles, 19 yellow marbles, and 29 green marbles. What is the % composition of each color marble in the bag?

Answers

Answer:

Red: 17.24%

Yellow: 32.76%

Green: 50%

Explanation:

Two solutions are mixed, bringing together ions of Na+, PO43−, V3+, and Cl−. Use the solubility rules to identify the composition of the salt that precipitates out of the solution.

Answers

What can you conclude about the father based on this passage? Check all that apply.

what is periodic law​

Answers

The Periodic Law states that the physical and chemical properties of the elements recur in a systematic and predictable way. When the elements are arranged in order of increasing atomic number. Many of the properties recur at intervals.

Who is my favourite wrestler?​

Answers

i don’t know:)))))))))))

Answer:

ma herdina thesto wrestling

14. Each beaker shown to the right contains iron and an
acid. In which beaker will the iron dissolve the fastest
and why?
a. Beaker A because of a higher concentration level.
b. Beaker A because of increased surface area.
C. Beaker B because of a higher concentration level.
d. Beaker B because of increased surface area.

Answers

The question is incomplete, the complete question is attached in the image below:

Answer: The correct option is D) Beaker B because of the increased surface area.

Explanation:

A solution consists of solute and solvent.

A solute is defined as a component that is present in a smaller proportion while a solvent is defined as a component that is present in a larger proportion.

Solubility is defined as the amount of solute that can be dissolved in a given amount of solvent to form a solution.

Solubility of a substance depends on a few factors:

Surface areaMolecular sizeTemperatureStirring effect

For the given images,

Beaker A has a large block of iron rod and Beaker B has iron shards.

The smaller molecular size of a substance increases its surface area and thus, increases the solubility.

Hence, the correct option is D) Beaker B because of the increased surface area.

bf3 can be octet or not​

Answers

Answer:

(BH3 follows the octet rule by dimerizing, as Hadi Kurniawan AR pointed out.) For H and He, an "octet" = 2 electrons. Boron does prefer to follow the octet rule, in that it likes to form borate compounds such as NaBH4. It also is happy to form compounds with elements with lone pairs.

describe how water molecules can hydrate various substances

Answers

Answer:

A water molecule can react with the carbonyl group of an aldehyde or a ketone to form a substance known as a carbonyl hydrate, as shown in the first reaction below. The carbonyl hydrates usually form a very small percentage of the molecules in a sample of a specific aldehyde or ketone.

(Nice profile pic also UwU)

can someone check if i did this right. thank you !!​

Answers

Answer:

noo

Explanation:

its basic

....................

Answer: acidic

Explanation:

I.
Look at the pictures below. What can you say about them?
Describe their similarities and differences. Write your answer in
your notebook
Www
cowo
Politics
SXO
is​

Answers

Answer:

Hey , I can't see the picture

why does shampoo remove hair grese for chemistry acids and alkali

Answers

because it’s shampoo


Pleaseee helpppp.....

Answers

Answer:

C. All of the above

Explanation:

They all happen beyond critical point.

This cell is dividing into two cells.

Answers

Answer:

answer: B or D

Explanation:

hope it helps thanks❤

Explain a polar molecules and give examples​

Answers

Ethanol is polar because the oxygen atoms attract electrons because of their higher electronegativity than other atoms in the molecule. Thus the -OH group in ethanol has a slight negative charge. Ammonia (NH3) is polar. Sulfur dioxide (SO2) is polar.

Which of the following elements is a metalloid (semimetal)?

C
P
Sb
N
In

Answers

Answer:

Sb

Explanation:

Sb (antimony) is an metalloid


How did reducing the number of
decomposers affect the amount of carbon
dioxide in the ecosystem?

Answers

Answer:

As organisms release energy during cellular respiration, carbon dioxide is produced from the carbon in energy storage molecules. ... Carbon dioxide in the biodome decreased because decomposers decreased which means there was a decrease in cellular respiration overall.

btw :

stay safe! :3

Nitrogen is a group 15 element. What does being In this group imply about the structure of the nitrogen atom?

Answers

Answer:

Nitrogen has 5 valence electrons

Explanation:

nitrogen has it's attoms form triple bonds which are very hard to break

so non-reactive

The food is good but it was okay and it wasn’t worth the price and it would not taste good for a one hour or so it just came in

12. Which nonmetal is the most reactive?
A bromine
B
iodine
C) fluorine
D) chlorine

Answers

Answer:

C Fluorine

Explanation:

C fluorine is the answer
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