What are some signs that a chemical change has occurred?

Answers

Answer 1

Answer:

Color Change.

Production of an odor.

Change of Temperature.

Evolution of a gas (formation of bubbles)

THe Precipitate (formation of a solid)

Explanation:

Answer 2
Colour change, change of temperature, gas present (so bubbles) and is there a smell.

Related Questions

Calculate the pH of a 0.002M acetic acid solution if it is 2.3% ionised at this dilution, ka=1.8×10^-5.

Answers

Answer:

3.11 is the pH of the solution

Explanation:

The ionised form of the acetic acid is the acetate ion. To solve this problem we need to solve H-H equation:

pH = pKa + log [A⁻] / [HA]

Where pH is the pH of the buffer

pKa = -log Ka  = 4.74

[A⁻] = Concentration of acetate ion = 0.002M * 2.3% = 4.6x10⁻⁵M

[HA] = Concentration of acetic acid = 0.002M *(100-2.3)% = 0.001954M

Replacing:

pH = 4.74 + log [4.6x10⁻⁵M] / [0.001954M]

pH = 3.11 is the pH of the solution

what is a climax community? no plagiarism.

Answers

Answer:

In scientific ecology, climax community or climatic climax community is a historic term for a boreal forest community of plants, animals, and fungi which, through the process of ecological succession in the development of vegetation in an area over time, have reached a steady state.

Explanation:

examine the diagram of the cell which or general is marked with an X help​

Answers

Answer:

I'm pretty sure it's the cell membrane

What happens in a single-replacement reaction?

A. One reactant breaks apart to form new compounds.
B. Two reactants combine to form one product.
C. Two reactants exchange elements with each other.
D. One reactant replaces an element in another reactant.

Answers

Answer:

D

Explanation:

A single-replacement reaction occurs when one element replace another in a single compound.

Which is evidence of climate-forced sea level rise submerging of low islands and coastlines decreased temperature of oceans temperature changes for surface currents increased carbon dioxide in the atmosphere​

Answers

Answer: Ocean rise?

Explanation:

Answer:

submerging of low islands and coast lines

Explanation:

earth science climate change unit test

What type of reaction is the one shown above?

Answers

Answer:

.D you have any idea

Explanation:

Sana makatulong

The net force of an object describes…

- The force that balances out the force of gravity
- All the forces in the same direction

Answers

Answer:

The vector sum of all forces that act upon an object

Think about and describe how the organism might move around and how it might eat.Required to answer.

Answers

Answer:

Organisms move and eat through their habitats. They adapt to the environment and can survive in the environment with their own behavior.

Explanation:

Organisms are of many types. Some lives on land, some lives in water while others are hybrid organisms which can survive in water as well as on land. The organisms body movement is dependent on its cell functioning. Every organism has different cell structures which help them to survive on the earth.

Molar Concentration of H2O+ lons
in Four Solutions
Solution Molar Concentration
of H3O+ lon
(M)
A 0.1
B 0.01
с 0.001
D I’m 0.0001
Which solution has the highest pH?

Answers

Answer:

d

Explanation:

because it’s moving the most spots to the left

The acidity or alkalinity of a solution depends upon its hydronium ion concentration and hydroxide ion concentration. Here among the given solutions, the solution D has the highest pH. The correct option is D.

What is pH?

The pH of a solution is defined as the negative logarithm to the base 10 of the value of the hydronium ion concentration in moles per litre. The pH scale is introduced by the scientist Sorensen. It is more easy to express the concentration of H₃O⁺ using this method.

The equation used to calculate the pH of the solution is given as:

pH = -log[H₃O⁺]

For 0.1 M

pH = -log[0.1] = 1

For 0.01 M

pH = -log[0.01] = 2

For 0.001 M

pH =  -log[0.001] = 3

For 0.0001 M

pH =  -log[0.0001] = 4

So solution D has the highest pH which is 4.

Thus the correct option is D.

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Is PCI3 a good conductor?

Answers

Answer:

Since the ions cannot move, ionic solids are non-conductors of electricity. When the solid is melted to a liquid, however, the ions are free to migrate. Therefore, ionic liquids are good conductors of electric current. A conductor is a substance capable of transmitting electricity and/or heat.

Explanation:

:)

No, [tex]PCI_3[/tex]  is not a good conductor.

What is [tex]PCI_3[/tex]?

Phosphorus trichloride is an inorganic compound with the chemical formula PCl3. A colourless liquid when pure, is an important industrial chemical, being used for the manufacture of phosphates and other organophosphorus compounds.

The liquid does not conduct electricity because of the lack of ions or mobile electrons.

Hence, no, [tex]PCI_3[/tex] is not a good conductor.

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WHAT IS THE PERCENT BY VOLUME OF ETHANOL IN A SOLUTION THAT CONTAINS 35 mL ETHANOL IN 115 mL OF WATER?

Answers

We need to first add both of the solution volumes together 35+115=150. Now we can divide the volume of the ethanol by the total volume 35/150=.233. To double check we can multiply the total volume by the percentage of ethanol by volume we got as a solution 150x.233=35. So the percentage by volume of ethanol in the solution is .233x100=23.3%.

What’s the answer for this question

Answers

Answer:

i think it's B

Explanation:

How many electrons does potassium, shown above, need to gain or lose to become stable?

Group of answer choices

gain 2

gain 1

lose 1

lose 2

Answers

Answer:

It would tend to lose two electrons and form a +2 ion. Potassium is in the first column and therefore has 1 electron in its outermost shell. It would tend to lose one electron and form a +1 ion.

What type of music do people like

Answers

Answer:

pop, emotional, heart touching, freestyle and rap music is what I LOVE!!!!!

Can someone help me with this please?

Answers

The answer would be D

9 Answer
Based on Table S, an atom of which element has the strongest attraction for electrons in a chemical bond

What is the answer?

1 aluminum
2 chlorine
3 magnesium
4 sulfur

Answers

Answer:

Chlorine

Explanation:

The tendency of an atom to attract electron is referred to as electronegativty. In the periodic table, electronegativity increases across the period from left to right and decreases down the group.

Following that trend, the element with the greatest electronegativty is;

Chlorine

The atom that has the strongest attraction for electrons in a chemical bond in the options is Chlorine.  

The tendency of an atom to attract electrons to itself is know as electronegativity.

The most electronegative element is fluorine.

Electronegativity increases across the period in the periodic table.

Electronegativity decreases down the group in the periodic table.

Examples of electronegative elements are mostly non metals like oxygen, fluorine, chlorine, etc.

Therefore, the atom that has the strongest attraction for electrons in a chemical bond is Chlorine.  

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A(n) ____________________ has a rectangular shape and contains a cell wall, chloroplasts, and one large vacuole.

Answers

I’m pretty sure the answer is “plant cell”

NaCl is purified by adding HCl to a saturated solution of NaCl (317 g/L). Will pure NaCl precipitate when 10mL of 13.0 M HCl is added to 0.2 L of saturated solution?

Answers

Answer:

Yes, pure NaCl will precipitate out of the solution

Explanation:

The parameters of the NaCl solution and HCl mixture are;

The saturation of the NaCl solution = Saturated solution

The mass concentration of the NaCl solution = 317 g/L

The volume of the HCl added = 10 mL

The concentration of the HCl added = 13.0 M HCl

The volume of the saturated NaCl solution = 0.2 L

The molar mass of NaCl = 58.44 g/mol

The number of moles of NaCl per liter = (317 g/L)/(58.44 g/mol) = 7925/1461 moles ≈ 5.42 moles

The ionization of the molecules in solution are;

HCl (aq) + H₂O (l) → H₃O⁺ (aq) + Cl⁻ (aq)

NaCl (s) ↔ Na⁺ (aq) + Cl⁻ (aq)

The number of moles of the Cl⁻ ion from the HCl is 13 moles per liter, the number of moles of Cl⁻ ion from the saturated solution of NaCl is approximately 5.42 moles, therefore, ionic product I.P. of the solution of Cl⁻ ions is larger than the solubility product of the solution, [tex]K_{sp}[/tex] of the NaCl and according to Le C h a t e l i e r's principle, NaCl will precipitate out of the solution

The following dot plot represents the litter sizes of a random sample of labrador retrievers.



Calculate the mean, median, and mode for this set of data.
Calculate the range, interquartile range, and mean absolute deviation (rounded to the nearest hundredth) for this set of data. For the mean absolute deviation, do not round the mean.
Make two inferences about the litter size of labrador retrievers.

Answers

Answer:

12

Explanation:so the mean deviation is for the square and the square is for you so you keep the square and add it.

Answer:

1. mean: 7.78 median: 8 mode: 7

2. range: 9 interquartile range: 2 MAD: 4.5367

3. The range is about 4 times bigger than the interquartile range. The mean is around double the MAD.

Explanation:

Which is a problem with using wind turbines to produce energy?
WA. Wind turbines are efficient only in certain areas.
A.
O C. Wind turbines produce a large amount of energy.
D. Wind turbines create a large amount of pollution.
B. Wind turbines occupy a small area of land.

Answers

Answer:

they are only efficient in certain areas

Explanation:

Wind turbine are efficient only in certain areas it is a problem with using wind turbines to produce energy.

What is Wind Turbine?

Wind turbine convert the wind energy into the electricity. It is a power generating device that converts the kinetic energy in to electrical energy.

                  

Now lets check all option one by one:

Option (A): Wind turbines are efficient only in certain areas it is a problem with using wind turbines to produce energy because the flow of air from areas of high pressure towards the lower pressure.

So, it is correct option.

Option (B): Wind turbines occupy a lot of space to work.

So, it is incorrect option.

Option (C): Wind turbines produce a large amount of energy is not a problem.

So, it is incorrect option.


Option (D): Wind turbines does not create a pollution or it does not pollute the air or water.

So, it is incorrect option.

Thus, we can say that Wind turbines are efficient only in certain areas it is a problem with using wind turbines to produce energy because the flow of air from areas of high pressure towards the lower pressure.

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determine the kinetic energy of an 833.0 kg roller coaster car moving at a speed of 20.0 m/s

Answers

Answer:

166,600J

Explanation:

Kinetic energy (K.E), which is the energy due to motion of a body, can be calculated by using the formula;

K.E = 1/2 × m × v²

Where;

K.E = kinetic energy (joules)

m = mass of body (kg)

v = speed or velocity (m/s)

According to this question, the mass of the roller coaster is 833.0 kg while its velocity/speed is 20.0m/s.

K.E = 1/2 × 833 × 20²

K.E = 1/2 × 833 × 400

K.E = 1/2 × 333200

K.E = 166,600

Therefore, the kinetic energy of the roller coaster car is 166,600J.

When a gas is heated, the gas particles have more kinetic energy. Complete the following sentence: This means they move about more and have more ______ with the sides of the container. This increases the pressure.

Answers

Answer:

Contact

Explanation:

As the speed of the particles increases, they move around more, which means they hit the sides of the container more.

Compound X has a molar mass of 104.01·gmol−1 and the following composition: element mass % nitrogen 26.93% fluorine 73.07% Write the molecular formula of X .

Answers

Answer: N2F4

Explanation:(NF2)x2 = N2F2

The compound X has a molar mass of 104.01·gmol−1 and the following composition: element mass % nitrogen 26.93% fluorine 73.07%, then the molecular formula of X is N2F4.

What is molecular formula?

Molecular formula is defined as a chemical formula that give the total number of atoms of each elements in each molecule of a substance.

It can also be defined as a phrase that specifies the number of atoms of each element in a complex molecule.

It represents the actual number of each atom in a molecules.

It tells us which atoms and how many of each types of atoms are present in a molecule.

NF2 x 2 = N2F4

Thus, the compound X has a molar mass of 104.01·gmol−1 and the following composition: element mass % nitrogen 26.93% fluorine 73.07%, then the molecular formula of X is N2F4.

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When you mix two substances, the heat gained by one substance is equal to the heat lost by the other substance. Suppose you place 125 g of aluminum in a calorimeter with 1,000 g of water. The water changes temperature by 2 °C and the aluminum changes temperature by –74.95 °C. Water has a known specific heat capacity of 4.184 J/g °C. Use the specific heat equation to find out how much heat energy the water gained (q). Assume that the heat energy gained by the water is equal to the heat energy lost by the aluminum. Use the specific heat equation to solve for the specific heat of aluminum. (Hint: Because heat energy is lost, the value of q is negative.)

Answers

From the calculation, the specific heat capacity of the aluminum is 9.5 * 10^-5  J/g °C

What is specific heat capacity?

The specific heat capacity refers to the heat that is required to raise the temperature of a body by 1K. The heat gained by the water is equal to the heat energy lost by the aluminum hence the negative sign.

Thus;

-(125 * c *  –74.95) = 1,000 g *  4.184 *  2

c =  1,000 g *  4.184 *  2/125 * 74.95

c = 8368/9368.75

c= 9.5 * 10^-5  J/g °C

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Which of the following best describes the distribution of the world’s food supply? Select all that apply.

Still unevenly distributed leaving millions starving to death.
Quickly changing to be evenly distribute based on humanitarian efforts.
Slowly changing to be slightly more evenly distributed based on humanitarian efforts.
Evenly distributed throughout the population of the world now.

Answers

Answer: It would be A and C

Explanation: I did the test and got it right. Hope this helps!

Answer:

A + C

Explanation:

ur an amazing person have a great day :3

quote for today : ~dont trust anyone to much remeber the devil was once angle

when HCl react with finely powdered iron it form ferrous chloride and not ferric chloride. why?​

Answers

Answer:

When iron is allowed to react with HCl,

It produces hydrogen and the release of hydrogen gas prevents the formation of ferric chloride.

Hope it helps

Thank you

Please mark me as brainliest.

238
U
92
+
Th
90
4
He
2
When radioactive uranium, or U-238, decays it emits an alpha particle and produces a nuclide of thorium. According to the nuclear
equation, what is the mass of the thorium produced?
A)
234
B)
238
C)
242
D)
244

Answers

Answer:

c) 242

Explanation:

you subtract 238-92= 146 then you add 146+90+4+2 that will give you 242

How many moles of silver atoms are in 3.88x10^20 atoms of silver

Answers

Answer:

100

ddExplanation:

Zinc chloride + Magnesium →

Answers

Answer:

im assuming you need the balanced equation

Explanation:

Zn + MgCl2 = ZnCl2 + Mg

Answer:

it will mgcl2 + zn

Explanation:

Mg will replace zn from its salt solution

to form mgcl2

hope it helps

NH4NO3->N2O+2H2O How many grams of NH4NO3 are required to produce 33.0 games of N2O

Answers

Answer:

the moles of N2O are 33/(14.2 + 16) = 0,75 (mol)

NH4NO3 ----------->  N2O + 2H2O

0.75          <---          0.75  

=> The moles of NH4NO3 are 0,75 mol

=> m = 0,75(14.2 + 4 + 16.3) = 60 (g)

Explanation:

Answer:

60 grams of NH4NO3

Explanation:

2222222c is right, but here's a better visualization of the answer!
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