What is the difference between an exothermic and an endothermic reaction?

A. Endothermic reactions absorb heat.

B. Exothermic reactions absorb heat.

C. There are no changes in heat during either reaction.

D. Endothermic reactions release heat.

Answers

Answer 1

answer D

Explanation:hope thhis helped


Related Questions

an atom contains positive protons and negative electrons. Why atom is electrically neutral. ​

Answers

Answer:

atom is electrically neutral because

the no.of protons is equal to no.of

electrons.

Therefore the negative charge and

positive charge cancels out.

Which of the following pairs of elements will form ionic bonds with each
other?
A. Silver (Ag) and silver (Ag)
B. Lithium (Li) and iodine (1)
C. Bromine (Br) and bromine (Br)
D. Carbon (C) and chlorine (CI)

Answers

Answer:

B. Lithium (Li) and iodine (1)

Explanation:

Ionic bond is a type of chemical bond that is formed between a metallic element and a non metallic element. The positive charge of the metallic ion is attracted to the negative charge of the non metallic ion to form an ionic bond.

According to the options given in this question, lithium and iodine will form an IONIC bond because lithium is a cation (+ve ion) while iodine is an anion (-ve).

What is a weak acid?
A. An acid that does not have a conjugate base
B. An acid that does not dissolve completely
C. An acid that has been diluted with water
D. An acid that has a very low pH value

Answers

Answer:

B

Explanation:

strong acids ionize completely in water

Answer:

An acid that does not dissolve completely

Explanation:

PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ HELP ME...... ​

Answers

Answer:

a) clockwise

b) clockwise and

c) anticlockwise

WILL MARK BRAINLIEST IF CORRECT

Answers

Answer:

3 - a heterogeneous mixture

4- Sweet tea is an homogeneous mixture

Answer:

Explanation:

6. d

7. b

8. c

The number of joules required to heat one gram of a substance one degree Celsius is _____.


endothermic

temperature

exothermic

specific heat capacity

Answers

The answer is D - specific heat capacity.

26. Calculate the mass of hydrogen formed when 25 grams of aluminum reacts with excess hydrochloride acid. 2AI + 6HCl →l Al2Cl6 + 3H2

Answers

Answer:

2.76 gram

Explanation:

2AI + 6HCl → 2AlCl3 + 3H2

get the mol of aluminum => n = m / M = 25 / 27 = 0.925 (mol)get the ratio mol of Hydro => nH2 = 0.925 * 3 / 2 = 1.38 (mol)get weight of hydro mH2 = n x M = 1.38 x 2 = 2.76 (gram)

Answer

Al +2 HCl - AlCl2 + H2

why do the aquatic plants not break down by water current?

Answers

Leaves of aquatic plants are covered by a waxy cuticle which does not allow the water to wet them.

What is an atomic mass unti

Answers

Explanation:

a unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.

Answer:

Atomic Mass Unit is also called Dalton. It is used to express atomic and molecular weight. It is defined as 1/12 of the mass of an unbound neutral atom of carbon.

Using these metal ion/metal standard reduction potentials calculate cell potential for Cu2+(aq) + Cd(s) →Cd2+(aq)+ Cu(s) Cu2+(aq)|Cu(s) + 0.34 VNi2+(aq)|Ni(s) -0.25 Cd2+(aq)/Cd(s) -0.4V

Answers

Solution :

Cd(s) ---------------------->  [tex]Cd^{+2}[/tex] (aq) + 2[tex]e^-[/tex]      ,     [tex]E_0[/tex]  =   0.34 v

[tex]Cu^{+2}[/tex]  (aq)  +   2[tex]e^-[/tex]  ------------> Cu (s)             ,     [tex]E_0[/tex]  =  -0.04 v

----------------------------------------------------------------------------------------------

Cd(s)  +  [tex]Cu^{+2}[/tex]  (aq)  ------------->  [tex]Cd^{+2}[/tex] (aq)  +  Cu (s)   ,      [tex]E_0[/tex]  =  0.30 v  

The cell potential is defined as the measure of [tex]\text{ potential difference }[/tex]  between the [tex]\text{two half cells}[/tex] of an electrochemical cell.  

Temperature is measured in what unit?


J

J/goC

J/g

oC

Answers

Temperature is measured in Kelvin..

name some examples of chemical solutions and maybe give a clear explanation as to what chemical solutions are ​

Answers

Answer:

Some examples of solutions are salt water, rubbing alcohol, and sugar dissolved in water. ... In our example of salt water, the solute is the salt. Solvent: this is the substance that makes up the majority of the solution. This is the part where the solute is dissolved.

Explanation:

I hope they should be right answer

hii pls help me to balance the equation thanksss​

Answers

Answer:

2H2S (g) + 3O2 (g) = 2H2O (l) + 2SO2 (g)

▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

[tex]\boxed{\pmb{\green{\sf{2H_{2}S(g) + 3O_{2}(g)\dashrightarrow 2H _{2}O(l)+2SO_{2}(g)}}}}[/tex]

▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

What are the standard temperature and pressure conditions enthalpy is usually measured under

Answers

Answer:

temperature must be 273 Kelvin (0°C)

pressure must be 1 atm

Determine the empirical formula for compounds that have the following analyses. a. 28.4% copper, 71.6% bromine b. 39.0% potassium, 12.0% carbon, 1.01% hydrogen, and 47.9% oxygen c. 77.3% silver, 7.4% phosphorus, 15.3% oxygen d. 0.57% hydrogen, 72.1% iodine, 27.3% oxygen

Answers

Answer:

See explanation

Explanation:

Cu- 28.4/63.5, Br- 71.6/80

Cu- 0.447/0.447, Br- 0.895/0.447

Cu- 1, Br - 2

Empirical formula = CuBr2

b)

K- 39.0/39, C-12.0/12, H- 1.01/1, O- 47.9/16

K= 1, C-1, H- 1. O-3

Empirical formula= KHCO3

c)

Ag- 77.3/108, P-7.4/31, O-15.3/16

Ag-0.716/0.239, P- 0.239/0.239, O-0.956/0.239

Ag-3, P-1, O-4

Empirical formula= Ag3PO4

d)

H-0.57/1, I- 72.1/127, O-27.3/16

H- 0.57/0.57, I- 0.57/0.57, O-1.71/0.57

H-1, I-1, O- 3

Empirical formula= HIO3

The boiling points of diatomic halogens are compared in the table.
Boiling Points of Diatomic
Halogens
Molecule
Boiling Point
F2
-188 °C
Cl2
-34 °C
Br2
59 °C
12
184°C
Which of the following statements best explains the trends in boiling points?
The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

Answers

Which of the following statements best explains the trends in boiling points?

A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.

                                           A is incorrect

B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.

                                            B is incorrect

C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.

                                             C is correct

D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

                                              D is incorrect

The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.

What is boiling point?

Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.

For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.

Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.

Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.

To find more about boiling point, refer the link below:

https://brainly.com/question/2153588

#SPJ1

3. A typical peanut butter and jelly sandwich contains 360 kcal, of which 160
kcal comes from fat. Given 1 kcal = 4.2 kJ, how many J of fat would there be
in one PB&J sandwich?

Answers

Explanation:

here's the answer to your question

Which factor would speed up a chemical reaction? (Choose all that apply)
Decreasing particle size
Increasing the temperature
Decreasing the temperature
Increasing particle size

Answers

Answer:

Increasing the temperature

Increasing particle size

Explanation:

Increasing the temperature allows for particles and molecules to move faster (because there is an increase in energy) and allows for more collisions.

∴ Increasing the temperature would be an answer.

Increasing the particle size allows for more surface area and a greater chance for particles to collide with each other.

∴ Increasing particle size would be an answer.

Topic: AP Chemistry

Unit: Kinetics

which state of matter expands most when heated​

Answers

Answer:

Gases expand the most upon heating because the intermolecular space is more than in solids or liquids.

Explanation:

hopes it helps

Gases
Gases expand the most upon heating because the intermolecular space is more than in solids or liquids.

Hope this helps

PLS MARK BRAINLY PLSSS

How many moles of oxygen are required to react completely with 5 mol C8H18?

Answers

Answer:

62.5 moles of O₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2C₈H₁₈ + 25O₂ —> 16CO₂ + 18H₂O

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Finally, we shall determine the number of mole of O₂ needed to react with 5 moles of C₈H₁₈. This can be obtained as shown below:

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Therefore, 5 moles of C₈H₁₈ will react with = (5 × 25) / 2 = 62.5 moles of O₂.

Thus, 62.5 moles of O₂ is needed for the reaction.

Predict the approximate Ksp of Cuz(AsO4)2 based on the measured potential of Cell 7. Use the equation given in the Background.

a. 1 x 10^-35

b. 4 x 10^14

c. 5 x 10^-17

d. 2 x 10^-21

Answers

Answer:

a. 1 x 10^-35

Explanation:

The correct compound given is: [tex]\mathsf{Cu_3(AsO_4)}_2[/tex]

To predict the approximate Ksp value of the given compound, we will need to express the oxidation-reduction half-reaction of the compound and its dissociation, then, we will use the Nernst equation to determine the approximate Ksp value.

To start with the reduction half-reaction:

[tex]\mathsf{Cu_3(AsO_4)_{2}(s) + 6e^- \to 2As O_{4}^{3-}_{(aq)}+3Cu(s) }[/tex]

The oxidation half-reaction is:

[tex]\mathsf{3Cu(s) \to 3CU^{2+}_{(aq)} + 6e^-}[/tex]

The overall cell reaction now is:

[tex]\mathsf{Cu_3(AsO_4)_{2}(s) \to 3Cu^+ (aq) + 2As O_{4}^{3-}_{(aq)} }[/tex]

From the reduction half-reduction, the number of moles of electrons (n) transferred is 6 moles.

By applying the Nernst equation:

[tex]\mathsf{E_{cell} = E^0_{cell} -\dfrac{0.0591V}{n}log [Cu^{2+}]^3[AsO_4^{3-}]^2 }[/tex]

At standard conditions;

The standard cell potential [tex]\mathsf{E^0_{cell} = -0.342 \ V}[/tex]

and [tex]\mathsf{E_{cell} = 0 \ V}[/tex] since it is at equilibrium.

[tex]\mathsf{0 = -0.342 -\dfrac{0.0591V}{6}log [Cu^{2+}]^3[AsO_4^{3-}]^2 } \\ \\ \\ \mathsf{0.342 = -\dfrac{0.0591V}{6}log [Cu^{2+}]^3[AsO_4^{3-}]^2 }[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 = \dfrac{-(0.342)*6}{0.0591 }}[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 = -34.7}[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 \simeq -35}[/tex]

[tex]\mathsf{[Cu^{2+}]^3[AsO_4^{3-}]^2 = 10^{-35}}[/tex]

[tex]\mathbf{K_{sp} = [Cu^{2+}]^3[AsO_4^{3-}]^2 = 1\times 10^{-35}}[/tex]


Which of the following are held together by nonpolar covalent bonds?
The Periodic Table
A. Atoms of phosphorus (P) and chlorine (CI)
B. Atoms of chlorine (CI)
C. Atoms of chlorine (CI) and magnesium (Mg)
D. Atoms of magnesium (Mg)

Answers

Answer:

Answer: Atoms of chlorine (CI) and magnesium (Mg)

Answer: Atoms of chlorine (CI) and magnesium (Mg)is your answer

Which phrase correctly describes the molecular structure within a molecule?

Answers

Same molecular structure and same properties.

Molecular structure is three dimensional structure in which arrangement of atoms is placed.

The molecular structure of a compound determines the polarity and its reactivity.

The different states of matter solid, liquid and gas have different molecular structure and different properties from each other.

The molecular structure of a molecule will have same properties as of the entire molecule based on its state.

Learn more at https://brainly.com/question/24325752

Answer:

the location of atoms, groups, or ions relative to one another and the number, type, and location of covalent bonds

"Every action force creates a reaction force that is equal in strength and opposite in direction." This statement summarizes Newton's

Answers

Answer: Newton's Third Law of Motion.

Explanation:

Newton's Third Law of Motion simply states that every action force creates a reaction force and then, this reaction force will be equal in strength and opposite in direction.

The statement simply implies that in every interaction, there will be a pair of forces that is acting on the two interacting objects. An example of Newton's third law of motion can be seen when a person jumps, thenlegs of the person will apply a force to the ground which will then propel the person into the air.

which is the answer?

Answers

Answer:

I could be wrong letter c

What will happen if we drink liquid nitrogen?

Answers

Because of its low temperature liquid nitrogen can be extremely damaging to body tissue, causing frostbite and cryogenic burning on contact. If ingested it can lead to severe internal damage, destroying tissue in the mouth and digestive tract.

What is the answer to 9.7300x10^2+9.8700x 10^3 1.0843x 10^ in scientific notation

Answers

Explanation:

Your search - What is the answer to 9.7300x10^2+9.8700x 10^3 1.0843x 10^ in scientific notation - did not match any documents.

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How many moles of Cd and of N are contained in 132.4 g of Cd(N03)2-4H20? (b) How many molecules of water of hydration are in this same amount?

Answers

Answer: The given amount of [tex]Cd(NO_3)_2.4H_2O[/tex] contains 0.430 moles of Cd, 0.860 moles of N and [tex]2.59\times 10^{23}[/tex] molecules of water.

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of [tex]Cd(NO_3)_2.4H_2O[/tex] = 132.4 g

Molar mass of [tex]Cd(NO_3)_2.4H_2O[/tex] = 308.5 g/mol

Plugging values in equation 1:

[tex]\text{Moles of }Cd(NO_3)_2.4H_2O=\frac{132.4g}{308.5g/mol}=0.430 mol[/tex]

1 mole of [tex]Cd(NO_3)_2.4H_2O[/tex] contains 1 mole of Cd, 2 moles of nitrogen atom (N), 10 moles of oxygen atom (O) and 8 moles of hydrogen atom (H).

So, 0.430 moles of [tex]Cd(NO_3)_2.4H_2O[/tex] will contain = [tex](1\times 0.430) = 0.430mol[/tex] of Cd and [tex](2\times 0.430)=0.86mol[/tex] of N

According to the mole concept:

1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules

So, 0.430 moles of [tex]Cd(NO_3)_2.4H_2O[/tex] will contain = [tex]\frac{6.022\times 10^{23}}{1mol}\times 0.430mol=2.59\times 10^{23}[/tex] number of water molecules.

Hence, the given amount of [tex]Cd(NO_3)_2.4H_2O[/tex] contains 0.430 moles of Cd, 0.860 moles of N and [tex]2.59\times 10^{23}[/tex] molecules of water.

I need help on this question asap!
You are in a lab and you use 11.50 g of Na(s) to react with Cl(g). Below is the reaction that happens from this.

Na + Cl2 → NaCl

Your percent yield is 95%. From this info what is the actual yield?

Answers

Answer:

27.79 g to the nearest hundredth.

Explanation:

2Na + Cl2 ---> 2NaCl

Using the molar masses , the theoretical yield is:

46 g of Na yields  46 + 35.5*2 g NaCl

46 g ---> 117 g NaCl  so

11.5 g ----> 117 * 11.5 / 46 g NaCl

But, as the yield is 90%

the actual yield is 0.95 * 117 * 11.5 / 46

= 27.79 g.

giúp tớ với, mình học lớp 9 ạ

Answers

Answer: broooo what is this

Explanation:

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