Which of the following observations is evidence used to imply that a chemical reaction has occurred? a. gas evolution b. a precipitate forms c. the color changes d. the temperature changes e. the odor changes f. a sound is produced g. change in taste ​

Answers

Answer 1

Answer:

burgers

Explanation:

Answer 2

Chemical reaction or chemical change is characterized by gas  evolution, precipitate formation and  the color changes.

What is a chemical change?

Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.

There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Related Questions

how to draw Bohr Model of Phosphorus?? ​

Answers

Answer:

look at the image below

Explanation:

The Bohr model of phosphorus depicts 15 electrons in different energy levels, with the nucleus at the center.

Two electrons are present in the first energy level, eight electrons are present in the second and five electrons are present in the third. The electron configuration of phosphorus, which is [tex]1s^2 2s^2 2p^6 3s^2 3p^3[/tex], matches this distribution.

The formula [tex]2n^2[/tex], where n is the energy level number, determines the maximum number of electrons in each energy level. Therefore, the first energy level can accommodate only two electrons, the second energy level up to eight, and the third energy level up to eighteen.

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How many grams of barium chloride (BaCl2) are there in 0.187 mol?
0.187 mol

Answers

Answer:

38.9 grams of [tex]BaCl_2[/tex]

Explanation:

0.187 mol BaCl2 x [tex]\frac{208 g}{1 mol}[/tex]

0.187 m x 208 g/m

0.187 x 208 g

38.896 g --> 38.9 g BaCl2

What does an elements location tell us about the forces within an atom?

Answers

Answer:

Forces inside the atom

The atom is comprised of three major particles—protons, neutrons and electrons. There are four forces (Electromagnetic, Strong, Weak, and Gravity) that are responsible for the behavior of the particles and thus keep the atom together.

Susan made observations about outside events she noticed throughout the day. The day began with rain. Susan saw puddles on the road. The rain stopped and the sun began to shine. The puddles disappeared. Later, clouds began to form in the sky. How do the parts of the water cycle relate to the events that Susan saw?

Answers

Answer:

Rainfall - precipitation

disappeared puddles - evaporation

cloud formation - condensation

Explanation:

Rainfall that is observed by the Susan is the precipitation of the water cycle in which the water vapor that was condensed become heavy and form droplets of water and fall from sky to the earth surface.

Puddles that formed due to rainfall are the collection of water in the water cycle which is evaporated (process: evaporation) into the atmosphere n the form of water vapor which condensed to form clouds.

Which of the following is NOT a type of scientist?
A. Geologist
B. Botanist
C. Meteorologist
D. Cryptologist

Answers

d. cryptologist is not a scientist

The density of this material is 2 g/cm^3.There are 24 cm^3.
What is the total mass?

Answers

Answer:

[tex]\boxed {\tt 48 \ grams}[/tex]

Explanation:

Mass can be found by multiplying the density by the volume.

[tex]m=d*v[/tex]

The density is 2 grams per cubic centimeter.

The volume is 24 cubic centimeter.

[tex]d= 2 \ g/cm^3 \\v=24 \ cm^3[/tex]

Substitute the values into the formula.

[tex]m= 2 \ g/cm^3 *24 \ cm^3[/tex]

Multiply. Note that the cubic centimeters, or cm³ will cancel each other out.

[tex]m= 2 \ g * 24[/tex]

[tex]m= 48 \ g[/tex]

The mass of the material is 48 grams.

5.
If 6.5 g of magnesium ribbon reacts completely
with hydrochloric acid, how many grams of
hydrogen gas would be liberated? Mg , + 2HC1(ag)
→ MgC1 + H, [H = 1.0, Mg = 24.0]

Answers

Answer:

The mass of hydrogen gas liberated is 0.6 g.

Explanation:

Given data:

Mass of Mg = 6.5 g

Mass of hydrogen gas liberated = ?

Solution:

Chemical equation:

Mg + 2HCl     →    MgCl₂ + H₂

Now we will calculate the number of moles of Mg.

Number of moles = mass / molar mass

Number of moles = 6.5 g/ 24 g/mol

Number of moles = 0.3 mol

Now we will compare the moles of Mg with hydrogen gas.

            Mg         :          H₂

             1           :           1

             0.3       :        0.3

Mass of H₂:

Mass = number of moles × molar mass

Mass = 0.3 mol × 2 g/mol

Mass = 0.6 g

What is the pH of a solution prepared by dissolving
0.8 g NaOH in water to make 200 mL solution?​

Answers

Answer:

pH>7

Explanation:

bases tend to increase the pH of a solution. since water has the pH of 7 and NaOH has pHof 14, the overall pH of solution will increase.

hope it's helpful.

Answer:

[tex]{\huge{\pink{\underline{\underline{Question:}}}}}[/tex]

What is the pH of a solution prepared by dissolving

0.8 g NaOH in water to make 200 mL solution?

[tex]{\huge{\pink{\underline{\underline{Answer:}}}}}[/tex]

pH>7

Bases tend to increase the pH of a solution.Since,water has the pH of 7 and NaOH has pH of 14, the overall pH of solution will increase.

5. One of Dr. Birdley's boxes has a
volume of 120 cm' and a mass of 2400 g.
The density of the rock is
a) 20 g/cm
b) 2520 g/cm
c) 240,480 g/cm
d) 2280 g/cm

Answers

Answer:

a.20g/cm

hope this helps :)

Explanation:

Which conclusion about the chemical reactivity of these elements is valid? Boron is the most reactive because it has the most protons. Fluorine is the most reactive because it has 7 electrons in the outer shell. Silicon is the most reactive because it has an equal number of protons and neutrons. Gallium is the most reactive because it has many more neutrons than protons.

Answers

Answer:

Fluorine is the most reactive because it has 7 electrons in the outer shell. The conclusion of this element's chemical reactivity is valid .

Explanation:

Among all the given elements - Boron ,Fluorine , Silicon and Gallium , Fluorine is the most reactive element because it has 7 electrons in the outer shell. It has a very small size and only requires one electron to get into a stable configuration with that of noble gases. Thus, to reach that stable state, they react spontaneously with elements, leading to its high reactivity.

Therefore, most reactive elements are in the halogen band, and none of the other three elements called Boron, Silicon and Gallium belong to the halogen group.

Hence, the correct answer is B (fluorine is the most reactive because it has 7 electrons in the outer shell).

If you have 128 atoms of a radioactive substance, with a half-life of 31 seconds, how many atoms would remain after 62 seconds? Please show your work.

Answers

Answer:

N = 32 atoms

Explanation:

The radioactive elements decays as follows:

Ln (N/N₀) = -kt

Where N are number of atoms after t time, N₀ are initial number of atoms, k is decay constant in time⁻¹

We can obtain k from t(1/2):

k = ln 2 / t(1/2)

k = 0.02236s⁻¹

Ln (N/128 atoms) = -0.02236s⁻¹*62s

(N/128 atoms) = e^-1.386

N/128 atoms = 0.25

N = 128 atoms * 0.25

N = 32 atoms

Compounds are pure substances. What other substances are considered pure substances?

Answers

Answer:

um... hydrogen gas

gold metal

sugar (sucrose)

PLS HELP ASAP

salt water is a pure substance
true or false?

Answers

Answer:

false

Explanation:

salt water cannot be classified as a substance because it's composition can vary

what information does the spectrum give about the source of the element?

Answers

Answer:

A continuous spectrum can identify elements by the presence of dark bands, and it also tells scientists how hot the object is: As the temperature goes up, the spectrum has increasing amounts of green, blue and violet colors. Relatively cool objects have a spectrum that has mostly deep red or red and yellow.

Explanation:

575/2000 in ratio please send me photos of this answer ​

Answers

Answer:

23 : 80

Not sure

No time for pictures

Answer:

[tex]{\huge{\pink{\underline{\underline{SoLuTiOn}}}}}[/tex]

Refer to above attachment...

How do you tell which isotope is more abundant?

Answers

Answer: To determine the most abundant isotopic form of an element, compare given isotopes to the weighted average on the periodic table.

A tea bag in a cup of hot water can be a simple model of a cell. Water moves into the tea bag and substances in the tea leaves move out through a thin layer of material. What does the thin material that holds the tea leaves represent? ​

Answers

Answer:

It represents a  partially permeable membrane

Explanation:

As the water is added to the teabag it causes the tea leaves to move and triggers diffusion of the leaves. ... The addition of heat (from the hot water) to the tea bag causes its molecules to move much faster than at room temperature

Answer:

The cell membrane

Explanation:

I checked it and it’s right on A P E X. I hope this helps!!

Proof:

A _____ state is when the electron is closest to the nucleus.

Answers

Answer:

ground state

Explanation:

A ground state is when the electron is closest to the nucleus.

What is the ground state of an atom?

The ground state of an electron is the state of the lowest energy for that electron. The nucleus is surrounded by electrons that occupy orbitals of varying energy levels.

When an electron jumps to an energy state greater than its ground state, then it is in an excited state. An electron can become excited from the ground state to the excited state if it is given extra energy in the form of a photon, or packet of light.

An electron occupies the lowest energy level that is closer to the nucleus when the electron is present in the ground state.

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2
1. Biology is the study of

Answers

biology is the study of life

Answer: biology is the study of life

Source:trust me bro

Ocean waves are limited in

Answers

Answer:

are there answer choices with the question?

Explanation:

sorry im a little confused

What is the KE at 1 m?

Answers

Answer:

K.E. = 1/2 m v2

Explanation:

which elements have similar chemical properties

A) Na, K, Mg

B) B, Al, S

C) N, O, F

D) He, Ar, Kr​

Answers

The anser is b i think that what i think

beeans beans beans beans beans!!

Answers

Answer:

points go brrrrrr

Explanation:

Answer:

Beans.

Explanation:

Which part of the wave does the arrow point to?
A. Rarefaction
B. Crest
C. Frequency
D. Trough






Help me ASAP please

Answers

Answer:

B

Explanation:

It was the correct answer when I answered it

The part of the wave that the arrow is pointing to is the crest.

Wave is defined as a disturbance that travels through a medium and transfers energy from one point to another without causing any permanent displacement of the medium itself.

The given diagram is a waveform. The waveform consists of a crest and a trough.

The trough is the minimum amplitude of the waveform while the crest is the maximum amplitude of the waveform

From the graph, the red dots are the crest of the graph while the blue dots are the trough.

Hence we can conclude that the part of the wave that the arrow is pointing to is the crest.

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interview at least three farmers in your community. ask them how they prepare their field for planting vegetable crops.And the common tools, implements and equipment they used in preparing for planting

Answers

Answer:

I think they use water,shovel,and rake.

Explanation:I was in ag in 8th grade and first we used a rake and raked all the stuff up. Then we waterd the dirt. Then dug a hole and planted the plant and waterd it after.

I hoped this help have a nice day! Comment if you need more help.

Also please rate 5 and give thanks.

Is the following equation balanced? Why or why not?
N, + 6H2 → 2NHO

Answers

Answer:

No

Explanation:

There is only one Nitrogen on the left side while there are 2 on the right. Also there is zero oxygen on the left side and two on the right. The amounts of hydrgen arent equal to each side either.

how many neutrons are present in the isotope of nobelium, No-254?

Answers

i believe that there is 152 neutrons in No-254

What is the mass of 6.02 × 10²³ hydrogen atoms​

Answers

Answer:

1.0 something depending on your periodic table.

Explanation:

You are given atoms. Not molecules. The mass is what you would read from the periodic table. 1.000 in some form is the answer.

In nature, Hydrogen is found as H2 everywhere except in the sun or a star. The molecular mass (not the atomic mass) would be 2.000 something.

Calculate the number of moles of neon gas in 8.15 atoms of neon gas

Answers

Answer:

13.5 moles Ne

Explanation:

Atoms --> Moles

1. Put the given number over 1

2. Multiply by 6.022x10^23 to get to moles

3. Round by sigfigs

(8.15x10^24 atom Ne(g)/1) (1 atom Ne(g)/6.022x10^23molesNe)=13.5337...

13.5337 --> 13.5 moles Ne

What’s the answer????

Answers

Answer:

all of above

Explanation:

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