Changes in the total amount of thermal energy provide evidence that chemical reactions have taken place. A chemical reaction in which energy has been absorbed is known as a(n):
Select one:
physical reaction.

endothermic reaction.

reversible reaction.

exothermic reaction.

Answers

Answer 1

Answer:

B. endothermic reaction

Explanation:


Related Questions

show the path to the formation of sodium calcium and aluminum bases please help me​

Answers

Answer:

i hope this helps :)

Explanation:

please mark brainlest

Answer:

dunno

Step-by-step explanations:

A mixture of four gases exerts a total pressure of 960
mm Hg. Gase A each exert 120 mm Hg. Gas B exerts
50 mm Hg. What pressure is exerted by gas C?

Answers

Omitted question:I think you mean Gas A and D each exert 120 mm Hg, if Gas D has a different value , just lug it into he equation as shown below and solve.

Answer:Gas C= 670mmHg

Explanation:

According to Dalton law of partial pressure

The total pressure of a mixture of gases is the sum of the pressures of each gas and can be illustrated as

Pressure total=P1+P2+… +Pn.

Total Pressure = Gas A + Gas B + Gas C + Gas D + Gas...

Now we have

Total Pressure = 120 mm Hg + 50mm Hg + Gas C + 120 mm Hg

960mmHg = 120 mm Hg + 50mm Hg + Gas C + 120 mm Hg

960mmHg =290mmHg +Gas C

Gas C =960mmHg -290mmHg

Gas C= 670mmHg

Convert the following problems:

a 96 kg to g

b 15 cL to kL

c 188 dL to L

d 3600 m to km

e 234 K to °C

f 43 °C to °F

i would really appreciate the help on this, I'm kinda struggling

Answers

Answer:

a.) 96000 g

b.) 0.00015 kL

c.) 18.8 L

d.) 36 KM

e.) -39.15 C

f.) 109.4 F

Explanation:

To turn kg to g, multiply the value by 1000

To Turn CL to KL, divide the volume value by 10000

To turn dl to l, divide volume by 10

to turn m to km, multiply meter value by 0.001 or divide by 1000

To convert c to f, multiply the temperature in degrees Celsius by 2, and then add 30

i hope this helps : )

This is agree or disagree I need help ASAP!!

Answers

Answer:

disagree

sometimes they attract

Explanation:

Answer:

Explanation:

2. Agree

3. Agree

4. Agree

5. agree

6. disagree

If im wrong its because im tired lol

Carbon dioxide and oxygen are both ___ found in the air.

Answers

Answer:

gases

Explanation:

Answer:

the Carbondioxed and oxygen are both a gass found in the air

how much atomic mass does Osmium have

Answers

Answer:

190.23g

Explanation:

Osmium is element number 76 on the periodic table, with the atomic symbol "Os." The atomic mass of any element is listed underneath the atomic symbol. Osmium has an atomic mass of 190.23 grams.

Use the Word Correctly in a Sentence

Ion

Answers

I am studying about Ions in my science class.

You and a friend are swimming at your grandparent's house one toasty

summer afternoon. You have music playing through the Bluetooth speaker

on the pool deck, but every time you go underwater, you can hear the

noise, but you cannot understand the words of the song. What would

explain this phenomenon? *

Sound waves travel faster in a gas than they do in a liquid, which is why you cannot

understand the words,

Sound waves travel faster in a liquid than a gas, our ears are just not designed to

translate the faster moving waves,

Sound waves cannot travel at all in a liquid, which is why you cannot understand the

words and it's a miracle you can even hear the music at all,

Sound waves travel at the same speed regardless of the medium; your grandfather is

turning the music on and off when you go underwater and the noise you hear is the

song stuck in your head,

Answers

Answer:

Sound waves travel faster in a liquid than a gas, our ears are just not designed to  translate the faster moving waves.

Explanation:

Sound waves are mechanical waves which travel through vibrating the medium (the "stuff") they're traveling through. This means they actually move faster through materials that are more dense, and will move more quickly through liquid than gas, and a solid than a liquid. However, our ears are adapted to "translating" sound waves in air rather than water, so we don't understand the music well when the waves move through the water.

A similar idea explains why our vision is blurry underwater; light waves travel at a different speed (slower, not faster!) in water and our eyes perceive this change in speed as blurriness.

Which 0.1 M solution has a pH greater than 7?
w
1. C6H1206
2.CH3COOH
3.КСІ
4.KOH

Answers

Answer:

4) KOH

Explanation:

Trust

0.1 M KOH has a pH greater than 7.

What is pH?

The pH of a solution is a measure of hydrogen ion (H+) concentration, which is, a measure of acidity.

What is POH?

The  pOH of a solution is measure of hydroxide ions (OH).which is a measure of basicity.

The pH of

CH3COOH is 2.88..КСІ is 7KOH is 12

∴According to the question the pH greater than 7 is KOH

Learn more about pH here: https://brainly.com/question/172153

#SPJ#

If 0.0015 moles of NaOH is dissolved in 11 L of water, what is the pH of the
solution?

Answers

Answer:

pH = 10.15

Explanation:

NaOH is a strong base so it dissolves completely.

Calculate your [OH-] first by dividing the moles of OH- by the volume.

0.0015 mol OH- / 11 L = 0.00014

Then, calculate the pOH:

pOH = -log[OH-] = -log(0.00014) = 3.85

pOH + pH = 14, so pH = 14 - pOH = 14 - 3.85 = 10.15

If the football indoors had a volume of 5.33 L at 21degrees celsuis, what is the volume of the football outside where the temp is 10C (temp must be in K) MUST SHOW WORK

Answers

Answer:

5.13 L

Explanation:

From the question given above, the following data were obtained:

Initial volume (V₁) = 5.33 L

Initial temperature (T₁) = 21 °C

Final temperature (T₂) = 10 °C

Final volume (V₂) =?

Next, we shall convert celsius temperature to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Initial temperature (T₁) = 21 °C

Initial temperature (T₁) = 21 °C + 273

Initial temperature (T₁) = 294 K

Final temperature (T₂) = 10 °C

Final temperature (T₂) = 10 °C + 273

Final temperature (T₂) = 283 K

Finally, we shall determine the final volume. This can be obtained as follow:

Initial volume (V₁) = 5.33 L

Initial temperature (T₁) = 294 K

Final temperature (T₂) = 283 K

Final volume (V₂) =?

V₁/T₁ = V₂/T₂

5.33 / 294 = V₂ / 283

Cross multiply

294 × V₂ = 5.33 × 283

294 × V₂ = 1508.39

Divide both side by 294

V₂ = 1508.39 / 294

V₂ = 5.13 L

Thus, the new volume of the football is 5.13 L

Based on what you have learned about the units for measuring thermal energy, complete the following passage.



The unit often used in chemistry and physics to measure energy, such as for work or electrical current, is the
. We can also use this unit, as we did in this lab, for measuring
. This is a property that is quantified by the energy needed per
of material to raise the temperature by one
. The unit for this measure is therefore
.

Answers

Answer:

1.joule 2.specific heat 3.gram 4.degree Celsius 5.J/g°C

Explanation:

I did the lab

Thermal energy is represented in the units joules J. It is the energy needed to raise the temperature by one degree celsius.Per gram this energy is called as specific heat capacity with the unit J/°Cmol.

What is heat capacity?

Heat capacity of a substance is the heat energy required to raise the temperature of the substance by one degree celsius.

If the heat capacity is measure per one mole of a substance it is called specific heat capacity. It is an intensive property whereas heat capacity is an extensive property.

The given passage can be completed as follows:

The unit often used in chemistry and physics to measure energy, such as for work or electrical current, is Joule (J). We can also use this unit, as we did in this lab, for measuring  heat capacity.  

This is a property that is quantified by the energy needed per one gram of material to raise the temperature by one degree celsius.The unit for this measure is therefore J/°Cg.

To find more about heat capacity, refer the link below:

https://brainly.com/question/28921175

#SPJ2

what is the molar mass of.
3 moles of iodine, 5 moles of gold, and 2.5 moles of potassium

Answers

Answer:

choices?

Explanation:

2.00g of Copper wire was added to 50.0 mL of a 0.050M solution of Silver Nitrate. The reaction
produced solid silver and aqueous copper II Nitrate. The silver precipitate was collected and
dried. It was determined that the mass of the silver precipitate was 0.24 g. Use this information
to determine the theoretical yield, limiting reactant, and percent yield.

Answers

Answer:

See explanation

Explanation:

Now, the equation of the reaction is;

Cu(s) + 2AgNO3(aq) --------> Cu(NO3)3 (aq) + 2Ag(s)

Number of moles of silver precipitate = 0.24/108 g/mol= 0.0022 moles

Number of moles of AgNO3 = 50/1000 * 0.050 = 0.0025 Moles

If 2 moles of AgNO3 yields 2 moles of Ag

Then  0.0025 moles of AgNO3 yields  0.0025 * 2/2 = 0.0025 moles of Ag

Number of moles of Cu = 2.00g/63.5 g/mol = 0.03 moles

If 1 mole of Cu yields 2 moles of Ag

0.03 moles of Cu yields  0.03 moles * 2/1 = 0.06 moles of Ag

Hence AgNO3 is the limiting reactant

Theoretical yield of Ag = 0.0025 moles of Ag * 108 = 0.27 g

Actual yield of Ag = 0.24 g

Percent yield = actual yield/theoretical yield * 100

Percent yield = 0.24/0.27 * 100

Percent yield = 88.8%

The following statements were stated by a politician who was paid by the nuclear energy lobby in a debate in favor of nuclear energy:



a. Nuclear energy doesn’t produce a byproduct because the atoms disappear.

b. Nuclear energy produces no polluting gas in its reaction.

c. Nuclear energy does not contribute to global warming.

d. Nuclear energy has low mining and transportation effects on environment.



Which statement is false and should not be used to argue in favor of nuclear energy?



A) Statement A

B) Statement C

C) Statement D

D) Statement B

Answers

Answer:

d

Explanation:

the best state ment is d lol

Indicate which aqueous solution has the highest boiling point elevation. (Kb for water = 0.512 °C/m)

Answers

Answer:

carbon tetrachloride

Explanation:

Boiling point elevation of a liquid or a compound is defined as the boiling point of a liquid that is that will be higher when some other other compound is added. It means that the solution has a higher boiling point than the solvent. When a non volatile solute is added to the pure solvent like water, it results in the highest boiling point elevation.

Carbon tetrachloride, Kb = 5.03°C/m shows highest boiling point elevation when it is used to make a 0.10 m non - electrolyte solution.  

You are melting a chocolate and accidentally have the stove up to high. the chocolate starts to burn on the bottom of your pot. Physical or Chemical Change?

Answers

Answer:

it is a chemical change because it can't be change back to it normal position when it gets burnt

Which is an example of a double
replacement reaction?
2Na+ Cl2 + 2NaCl
H2SO3 → H20 + S02
2K + 2H20 – 2KOH + H2
NaCl + AgF-NaF + AgCI

Answers

this is an example of displacement reaction
NaCl + AgF-NaF + AgCI

help please see attached file

Answers

Answer:

balanced equation of glucose

6CO2 + 6H2O----------C6H12O6 + 6O2

in the presence of sun light.

Biomes are characterized by temperature, precipitation, and the plant and animal communities that live there.
True or false?

Answers

Biomes are typically characterized based on the dominant plant and animal species found in a certain geographic area. Temperature and precipitation are what determine the geographic distribution of a biome which species can live there.

False

A student makes observations about a piece of copper. Which
observation describes a chemical property of the copper? (*hint: anything
relating to "measurements" of something is a physical property) *
A. it has a mass of 63.546 grams
B. corrosion occurs when it is exposed to air
C. it has a density of 8.96 g/cm^3

Answers

Answer: b

Explanation:

Ohio Achievement Test Coach Science, Grade 5
10. Bob first blows whistle hard. Then he blows the same whistle gently. What
changed when Bob blew the whistle the second time?
POSTTEST
A pitch
B. volume
C. pitch and volume
D. frequency

Answers

I think it’s the frequency? Because it lower his voice when he whistle again

A student asks why the ashes from a fire have much lower mass than the wood that was burned. Which of the following is the correct answer to the student's question?

Answers

Answer:

It have lower mass because much of the ashes came from the burned wood. (ashes were like little parts of the wood). plus most of the fuel was turned in to fire (light and heat energy) so yeah ash is just the left over.

Explanation:

4. Explain how radioactive isotopes are used to detect health problems.

Answers

Radioisotopes are widely used to diagnose disease and as effective treatment tools. For diagnosis, the isotope is administered and then located in the body using a scanner of some sort.

Which of the following represents the molecules of one compound and
atoms of one element?

Answers

Answer:

i think its b.c but I'm not sure

Answer:

A

Explanation:

A is element as all of them look the same

b is mixture of atoms

C is mixture of atoms and compounds

D is just atoms

E is mixture of element and compound

please help there is a pic and marking brain list

Answers

Answer:

3

Explanation:

It’s all of the above

What volume is occupied by 2.33 miles of an ideal gas at 0.953 atm and 44°C

Answers

Answer:

6663.6

Explanation:


What is the percent composition (by mass) of MgBr2?

Answers

Answer:

13.2% Mg, 86.8% Br

Explanation:

Mg has a molar mass of 24.31g/mol.

Bromine has a molar mass of 79.90 g/mol.

There is one mole of Mg and two moles of Br in the compound:

79.90x2 + 24.31 = 184.11

So the total molar mass of MgBr2 is 184.11.

A percent tells us a part of a whole, so we will divide each part of the mass into the whole mass.

24.31g Mg / 184.11g MgBr2 = .132

159.8g Br / 184.11g MgBr2 = .868

Multiply these decimals by 100 to make them into a percent.

.132 x 100 = 13.2% Mg

.868 x 100 = 86.8% Br

describe each of the three states of matter (solid, liquid, gas)​

Answers

Explanation:

In a solid particles are firmly together and are stuck in a regular pattern

in a liquid particles still touch but arent in a fixed pattern

in a gas particles move quickly in all directions

All changes in phase (solid-liquid-gas) are

Answers

Answer:

States of matter

Explanation:

Three states of matter

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