A chemical reaction causes the chemical compositions of substances to change.

a. True
b. False

Answers

Answer 1

Answer:

True

Explanation:

A chemical change is otherwise known as a chemical reaction. A chemical change is characterized by the formation of new substances, evolution of heat and change in chemical composition of substances. The change in the composition of substances during a chemical change is the result of the making and breaking of chemical bonds during a chemical change.

A chemical change is not easily reversible because it involves changes in chemical composition of substances.

An example of a chemical change is the combination of sodium hydroxide and hydrochloric acid according to the reaction equation;

HCl(aq) + NaOH (aq) -----> NaCl(aq) + H2O (l)

We easily notice the change in the chemical composition of each of the substances involved in the reaction.


Related Questions

formation of SO3 from SO2 and O2 is favoured by
a) increase in pressure
b) decrease in pressure
c) Increase in temperature
d)decrease in temperature​

Answers

Answer:

answer is A. increase in pressure

l think this correct answer

What is the atomic mass of hafnium if, out of every 100 atoms, 5 have a mass of 176, 19 have a mass of 177, 27 have a mass of 178, 14 have a mass of 179, and 35 have a mass of 180.0? Answer with 2 decimals

Answers

Answer:

178.36 a.m.u

Explanation:

5 have a mass of 176,

5/100 * 176 = 8.8

19 have a mass of 177

19 / 100 * 176 = 33.44

27 have a mass of 178

27 / 100 * 178 = 48.06

14 have a mass of 179

14 / 100 * 179 = 25.06

35 have a mass of 180.0

35 / 100  * 180 = 63

Atomic Mass = 8.8 + 33.44 + 48.06 + 25.06 + 63

Atomic Mass = 178.36 a.m.u

The action of a tree stump splitting bedrock depicts what type of process?

А. chemical weathering

B. physical weathering

С. deposition

D. erosion

Answers

B. Physical weathering

Answer: Physical Weathering

Explanation: It is physical weathering because it is caused by natural elements causing the rock to break. It is not chemical weathering because it is not using any chemical reaction to break the rock. It is not erosion or deposition because it is still not finished with the process with breaking the rock. Think of it this way:

Step 1: Weathering - Breaks rock/stone

Step 2: Erosion - Taking the small bits of rock

Step 3: Deposition - Dropping the rock

In a neutralization reaction, bases donate.

Answers

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Answer: I think it is hydroxide ion but im not sure

Explanation:

I hope this helped!

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What is the total number of nitrogen atoms in two mol of NH4NO3?

Answers

Answer:

the answer is B if one mol contains of NH4NO3 contains 6.02X 10^23

the answer would be B “6.02 x 10^23. If one mol of NH4NO3 contains 6.022 x 10^23 molecules of NH4NO3, and each molecule contains two nitrogen atoms (notice the two Ns representing nitrogen in the chemical formula), then there are 2 x 6.022 x 10^23 nitrogen atoms in two mol of NH4NO3

The answer for this

Answers

it should be c since the

2C2H2 + 502 = 4CO2 + 2H20
when 20000g of 2C2H2 + 5O2 = how much 4CO2?​

Answers

Answer:

6.761 × 10⁴ g

Explanation:

Step 1: Write the balanced combustion reaction

2 C₂H₂ + 5 O₂ ⇒ 4 CO₂ + 2 H₂O

Step 2: Calculate the moles corresponding to 20000 g of C₂H₂

The molar mass of C₂H₂ is 26.038 g/mol.

20000 g × 1 mol/26.038 g = 768.11 mol

Step 3: Calculate the moles of CO₂ produced from 768.11 moles of C₂H₂

The molar ratio of C₂H₂ to CO₂ is 2:4.

768.11 mol C₂H₂ ×  4 mol CO₂/2 mol C₂H₂ = 1536.2 mol CO₂

Step 4: Calculate the mass corresponding to 1536.2 moles of CO₂

The molar mass of CO₂ is 44.01 g/mol.

1536.2 mol × 44.01 g/mol = 6.761 × 10⁴ g

1) This rock is made out of cooled magma.

A) Igneous

B) Sedimentary

C) Metamorphic

D) Sandstone


2) This type of rock is made through the processes of heat and pressure.

A) Igneous

B) Sedimentary

C) Metamorphic

D) Sand



3) Sandstone is a sedimentary rock. How does sandstone form?



A) It melted and cooled.

B) It broke into sediment and then compacted.

C) It was heated and put under pressure.

D) Rocks don’t form; they stay as they are.



4) What type of rock can be broken down into sediment through weathering?

A) Igneous

B) Sedimentary

C) Metamorphic

D) All types of rocks



5) How does rock from a mountain turn into small pieces of rock?

A) Wind and rain break the rock into small pieces.

B) Earthquakes and natural disasters break the rock.

C) The sun's rays break the rock.

D) Everything breaks into pieces if you leave it out.



6) Can igneous rock underneath Earth’s outer layer change into sedimentary rock?

A) Yes, but it must be subducted first.

B) Yes, but it must be weathered first.

C) Yes, but it must be uplifted first.

D) No, igneous rock can never become sedimentary.



7) This energy source creates magma, which is melted rock that will turn into igneous rock.

A) Sun

B) Air

C) Earth's Interior

D) Water


8) This energy source helps create weather, which creates sediment to form sedimentary rocks.

A) Air

B) Sun

C) Water

D) Earth's Interior


9) What is the difference between magma and lava?


A) Magma is very hot, lava is cool.

B) Magma is molten rock within the earth; lava is molten rock on the earth's surface.

C) Magma is molten rock on the earth's surface; lava is molten rock within the earth.

D) Magma is cool, lava is very hot.

Answers

1. a) Igneous.

2. c) Metamorphic.

3. b) It broke into sediment and then compacted.

4. d) All types of rocks.

5. a) Wind and rain break down the rock into small pieces.

6. a) Yes, but it should be subtuced first.

7. c) Earth's interior.

8. c) Water.

9. b) Magma is molten rock within the Earth; lava is molten rock on the Earth's surface.

Na + H2O = NaOH
Balance the following equation

Answers

2Na + 2H2O ——> 2 NaOH + H2

Answer:

Na+H2O =NaO+ H2

Explanation:

Because nitrogen is one , so it is balanced. And Oxygen is one,it is balanced. And Hydrogen is 2 ,and hence it is also balanced.

- Explain why the term greenhouse effect is used to describe the theory of global
warming.
Does the greenhouse effect affect life on Earth? If yes, explain how?
What are the possible effects of a buildup of greenhouse gases in our atmosphere?

Answers

The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat. This process makes Earth much warmer than it would be without an atmosphere. It is one of the things that makes Earth a comfortable place to live.

If 3 moles of NaOH is dissolved in 4L of water, what is the
molarity of the solution?

Answers

Answer:

0.75mol/LNaOH

Explanation:

Data: Soln:

M= ? M= n/ V(l)

n= 3moles. M= 3mol/ 4L

V= 4L. M = 0.75 mol/LNaOH

1,3,5,7-Cyclooctatetraene, C8H8, is an unusual hydrocarbon in that it reacts with exactly 2 equivalents of potassium to give A, C8H8K2, which can be isolated as a white solid. A exhibits a single proton NMR signal. Draw the structure of A

Answers

Answer:

Explanation:

The main assignment here is to provide the structure of A. But before that, let us explain briefly some certain things:

The proton NMR (1H) gives data about the quantity of non-identical protons present in the structure. The resonance frequency is seen regarding the standard compound (0 ppm), which is addressed as a chemical shift. The same protons have equal value of chemical shift.

The protons that are available in a similar environment are addressed as comparable protons and the protons with various conditions are called non-identical protons.

However, from the image below, we can see the reaction of the compound 1,3,5,7-cyclooctatetraene resulting in 2 equivalents of potassium forming an aromatic dianion.

The heat of a reaction may be found with the equation q=mc triangle T. A 951 g sample of carbon steel with a specific heat capacity of 0.49 J/(g*K) is heated to 673K and quenched in oil. The steel cools to 523K. Assuming there is no heat lost to the surroundings, calculate the heat absorbed by the oil. A) -69.9kj B) -31.5kj C) 69.9 kJ D) 71.2 kj

Answers

Answer:b

Explanation:

Answer:

C.

Explanation:

I took the quiz and made a 100

Which is a similarity between a fish embryo and a bird embryo in the early stages of development?
Gill slits
forelimbs
jaw bones
hindlimbs

Answers

Hindlimbs should be the answer

Answer:

Gill Slits

Explanation:

For the one who asked what hind limbs are they are back legs :)

Use the following balanced reaction to solve 1-3:
P4 (s) + 6H2 (g) → 4PH3 (g)

How many grams of phosphorus trihydride will be formed by reacting 60 L of Hydrogen gas with an excess of P4?

Answers

Answer:

60.86 g of PH₃

Explanation:

We'll begin by calculating the number of mole of H₂ that will occupy 60 L. This can be obtained as follow:

22.4 L = 1 mole of H₂

Therefore,

60 L = 60 / 22.4

60 L = 2.68 mole of H₂.

Next, we shall determine the number of mole of PH₃ produced by the reaction of 60 L (i.e 2.68 mole) of H₂. This can be obtained as follow:

P₄ + 6H₂ –> 4PH₃

From the balanced equation above,

6 moles of H₂ reacted to produce 4 moles of PH₃.

Therefore, 2.68 moles of H₂ will react to to produce = (2.68 × 4)/6 = 1.79 moles of PH₃.

Finally, we shall determine the mass of 1.79 moles of PH₃. This can be obtained as follow:

Mole of PH₃ = 1.79 moles

Molar mass of PH₃ = 31 + (3×1)

= 31 + 3 = 34 g/mol

Mass of PH₃ =?

Mass = mole × molar mass

Mass of PH₃ = 1.79 × 34

Mass of PH₃ = 60.86 g

Thus, 60.86 g of PH₃ were obtained from the reaction.

A compound accepts electrons from another substance to form a covalent bond. Which term best describes this
compound's behavior?
-Lewis acid
-Arrhenius base
-Bronsted-Lowry acid
-Bronsted-Lowry base

Answers

Answer:

A). Lewis Acid

Explanation:

deez

The term that best describes the compound that accepts electrons from another substance to form a covalent bond is Lewis acid.

What is Lewis acid?

Lewis acid is a compound or ionic species which can accept an electron pair from a donor compound while a Lewis base is a compound such as the OH- ion, that can donate a pair of non-bonding electrons.

According to this question, a compound accepts electrons from another substance to form a covalent bond.

Therefore, the term that best describes the compound that accepts electrons from another substance to form a covalent bond is Lewis acid.

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Calculate the molarity of a solution that contains 3.00x10-2 mol NH4Cl in exactly 450 cm3 of solution.

Answers

Answer:

0.06moles/litres

Explanation:

molarity = no of moles / volume in litres = 3.00*10^-2/(450/1000)=0.06 moles/litres

Answer:

0.07mol/dm^3

Explanation:

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Simone is helping her mom cook. She takes a glass casserole dish directly from the refrigerator and put it in the oven. Which best explains the result of putting the cold dish in the hot oven?
Group of answer choices

The dish stays cool and will not warm.

The dish quickly changes color.

The dish cracks or breaks.

The dish contracts and shrinks.

Answers

Answer:

I think the dish contracts and shrinks

Answer:

The dish cracks or breaks.

Explanation:

When glass changes temperature rapidly, it may undergo thermal shock. This is stress that is produced by a sudden change in temperature.

what does pen mean?.

Answers

Answer:

P = protons

E = electrons

N = neutrons

remember protons and neutrons (protons are positive and neutrons are neutral as you can already tell by their names) are found at the centre of the nucleus (positive mass). Whilst the electrons (negative) orbit around the shells

A gas has an initial pressure of 2065 mmHg and temperature of 416 K. What is
the new pressure in atm if the temperature is cooled to 382 K?

Answers

Answer:

1896 mmHg

Explanation:

P1/T1 = P2/T2

P1 = 2065 mmHg

T1 = 416 K

P2 = ?

T2 = 382 K

Solve for P2 --> P2 = P1T2/T1

P2 = (2065 mmHg)(382 K) / (416 K) = 1896 mmHg

what career field/job would utilize ppm units
A environmental jobs
B Medical fields
C Jobs at the brewery
D Jobs in analytical chemistry

Answers

Jobs in analytical chem tht is because it’s parts per million and when calculating the amount of an element in a mole

How many moles is equal 82.4 grams of CO,?

Answers

Answer:

1 mole = 28.0101

Hence,

82.4 = around 2.8 mole

Have a great day <3

Rank the following compounds in order of decreasing acidity. Be sure to answer all parts. A) Benzyl alcohol B) Methylbenzene C) Benzoic acid

Answers

Benzyl alcohol = 15.4
Methyl benzene = 41
Benzoic acid = 5

so
B , A , C

The order of decreasing the acidity of the given compounds:

Benzoic acid > Benzyl alcohol > Methylbenzene.

What is the acidic strength?

The acidic strength of an acid can be described as the ability of the acid to lose its H⁺ ion. In general, the dissociation of acid can be represented as:

HA  →  H⁺  +  A⁻

Some examples of strong acids are hydrochloric acid, sulfuric acid (H2SO₄), perchloric acid  (HClO₄), etc.

The benzoic acid is a very strong acid with pka value of 4.5 as it contains the (-COOH) group. The Benzyl alcohol with pka value of 15.4 as it contains the (-CH₂OH) group attached to the benzene ring. The methylbenzene with pka value of 41 has the lowest acidity as it contains the methyl group attached to the benzene ring.

Therefore, the order of acidic strength for the given compounds is  Benzoic acid > Benzyl alcohol > Methylbenzene.

Learn more about acidic strength, here:

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Which compound is more soluble in water at 25°C?
A.
MgF2 (Ksp = 5.2 x 10-11)
B.
SrF2 (Ksp = 7.9 x 10-10)
C.
AgBr (Ksp = 5.0 x 10-13)
D.
Agl (Ksp = 1.5 * 10-16)

Answers

Answer:

B

Explanation:

The solubility depends on the ksp. As the value of ksp increases the compound becomes more and more soluble.

In the options, the highest ksp value is 10^-10, thus that one is the most soluble.

What do scientists mean when they refer to population

Answers

population is the number of species living in a given area if this is regarding biology or earth studies :)

The number of people


1. Calculate the percent composition of the elements in C4H8O2.

Answers

Answer:

%C = 54.53%

%H = 9.144%

%O = 36.32%

Explanation:

Step 1: Calculate the mass of each element in 1 mole of C₄H₈O₂

We will multiply the number of atoms by the molar mass of the element.

mC: 4 × 12.01 g = 48.04 g

mH: 8 × 1.007 g = 8.056 g

MO: 2 × 16.00 g = 32.00 g

Step 2: Calculate the mass of 1 mole of C₄H₈O₂

We will sum the previously calculated masses of the elements.

mC₄H₈O₂ = mC + mH + mO = 48.04 g + 8.056 g + 32.00 g = 88.10 g

Step 3: Calculate the percent composition of each element

We will use the following expression.

%Element = mElement / mCompound × 100%

%C = 48.04 g / 88.10 g × 100% = 54.53%

%H = 8.056 g / 88.10 g × 100% = 9.144%

%O = 32.00 g / 88.10 g × 100% = 36.32%


Which general equation represents an endothermic reaction?
A. reactants - energy - products + energy
B. reactants
products + energy
C. reactants + products - energy
D. reactants + energy
products

Answers

Explanation:

The general equation for an endothermic reaction is: Reactants + Energy → Products.

Hope it helps :)❤

The equation represents an endothermic reaction is reactants + energy

products.

What is an endothermic reaction?

Endothermic reactions are chemical reactions in which the reactants soak up warm strength from the surroundings to form products.

net energy is not released.heat is not evolved with the product.heat is required to start the reaction.increase with the increase in temperature.decrease with a decrease in temperature.

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The cell wall regulates what enters and exits the cell? True or False

Answers

Answer:

True

Explanation:

Answer:No, the Cell Membrane does I'm pretty sure

Explanation:

Balance Chemical Equations, will give brainiest.

Answers

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1) 2KCIO3=2kci+3o2

2)CH4 + 2O2 → CO2 + 2H2O

3)  2HCl + Ca(OH)2 → CaCl2 + 2H2O

I hope this helped!

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Lets make this one quick.

Answers

B because the answer was on my screeen
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