how do we know that a chemical reaction occured

Answers

Answer 1

Answer: signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.

Explanation:

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Related Questions

What kind of reaction is photosynthesis?

Answers

Answer:

endothermic reaction

Photosynthesis is an endothermic reaction. This means it cannot occur without energy (from the Sun). The light required is absorbed by a green pigment called chlorophyll in the leaves.

Explanation: hope this helps u!

Answer:

Endothermic reaction I believe.

Explanation:

It can't occur without the energy from the sun. The light is absorbed by the green pigment called chlorophyll which is in the leaves of the plant.

particles of liquids have enough energy to separate from other liquid particles true or false

Answers

Answer:

False

Explanation:

I particles have enough kinetic energy to partly overcome the force of attraction between them, matter exists as a liquid. The particles can slide past one another but not pull apart completely. This explains why liquids can change shape but have a fived volume.

It is false hope this helps

are soft pretzels, (like the auntie annes ones you get at the mall) made through the process of convection, conduction or radiation? thank youuu so much if you can answer ur the best

Answers

Answer:

I believe it's radiation, but please correct me if I'm wrong.

Explanation: Have a good day !

HELP ASAP _is a device with a central catheter that is implanted in the subcutaneous tissue
A.Leuer lock
B.Port
C.Cannula
D.Catheter

Answers

........The answer is A

Jennifer has a mass of 60 Kg and
is accelerating down the hill at a
rate of 3 m/s/s. What is the force
acting on Jennifer?

Answers

Answer:

the force acting on Jennifer is 180 N

Explanation:

The computation of the force acting on Jennifer is shown below:

As we know that

Force = mass × acceleration

= 60 kg × 3 m/s

=  180 N

hence, the force acting on Jennifer is 180 N

We simply applied the above formula

please answer as quick as possible

Q2. Which of the following elements is an alkali metal
A Potassium
B Chlorine
C Neon
D Krypton

Answers

Answer:

A - potassium........ M

Answer:

POTASSIUM

Explanation:

There are three bulbs powered by a battery. What will happen if the middle light burns out.

Answers

Answer:

ABC

Explanation:

The diagram shows the structure of an animal cell.
Which number label represents the cell membrane? (5 points)

Answers

Answer:

1

Explanation:

The cell membrane is the protective, semi-permeable membrane surrounding a cell and its contents.

Answer:

I think 19 I think I don't know

Please help me with this

Answers

323.5g - 301.2g = 22.3g is the change in mass.

The tectonic plates float on the lower portion of Earth's crust?

Answers

Answer:

The tectonic plates comprise the bottom of the crust and the top of the Earth's mantle. There are ten major plates on Earth and many more minor ones. They float on a plastic-like part of the Earth's mantle called the asthenosphere.

Explanation:

Answer:

Yes

Explanation:

what are the good and bad effects of bacteria​

Answers

Answer:

they are bacteria

Explanation:

Answer:

Good bacteria keeps you healthy by supporting your immune function and controlling inflammation. Certain types of good bacteria can also: Help your body digest food. Keep bad bacteria from getting out of control and making you sick.

Explanation:

I hope this helps and pls mark me brainliest :)

how many valence electrons are transferred from each potassium atom to nitrogen in the formation of the compound potassium nitride?

Answers

Answer:3 electrons

Explanation:

what is a respiratory system

Answers

Answer:

Body system that helps to breathe

Explanation:

Hope this helps! follow and message me in the comments if u need more explanation!

Answer:

The respiratory system consists of the set of organs and tissues involved in the uptake of oxygen from the atmosphere and the release of carbon dioxide generated during aerobic respiration. This gas exchange is also called breathing or external respiration.

Explanation:

How many moles of each element are in one mole of Be(OH)2? (3 points)
a. 1 mole of beryllium, 1 mole of oxygen, 2 moles of hydrogen
b. 1 mole of beryllium, 2 moles of oxygen, 2 moles of hydrogen
c. 2 moles of beryllium, 2 moles of oxygen, 2 moles of hydrogen
d. 2 moles of beryllium, 1 mole of oxygen, 1 moles of hydrogen

Answers

Answer:

b

Explanation:

Answer:

B

Explanation:

How can you tell, from the drawings, that gravity is greater on Earth
than on Venus?

‼️ Physics‼️

Answers

Answer:

hi basically also also Aussie

WILL GIVE NRAINLIEST!! NEED HELP FAST

7. (50 points) If you have 25 grams of Aluminum (Al), how many moles of hydrogen
gas (H) can you make? Show work!

Answers

Hello,

I believe this is (25 g Al) * (1 mol H / 1.008 g H) = 24.8015 mol H

Hopefully that was the right approach.
I thought that if one mole of Al is
26.982 g, then the numbers of moles for H (1.008 g/mol) would be about 25 mol.
If it doesn’t make sense or if you have resources/notes to which I can refer, I’ll see what I can do!

Good luck!

1. How many atoms of oxygen are present in 0.04 mole NaNO3?

2. How many moles of nitrogen atoms are present in 10.5g of N2O5?

3. How many atoms of oxygen are present in 50g of Fe(H20)2(S04)3? Please answer fast

Answers

Answer:

1. 7.227x10²⁴ O atoms

2. 0.1944 mol

3. 3.18x10²³ atoms

Explanation:

1. To solve this problem we need to use Avogadro's number, which states the number of molecules that are in 1 mol of a substance:

0.04 mol NaNO₃ * 6.023x10²³ molecules/mol = 2.409x10²⁴ molecules NaNO₃

There are 3 O atoms per NaNO₃ molecule, thus the answer is (3* 2.409x10²⁴) 7.227x10²⁴ atoms.

2. First we convert 10.5 g of N₂O₅ into moles, using its molar mass:

10.5 g N₂O₅ ÷ 108 g/mol = 0.0972 mol N₂O₅

There are 2 N moles per N₂O₅ mol, thus the answer is (2*0.0972) 0.1944 mol.

3. First we convert grams into moles:

50 g Fe(H₂O)₂(SO₄)₃ ÷ 379.85 g/mol = 0.132 mol

Then we use Avogadro's number:

0.132 mol * 6.023x10²³ molecules/mol = 7.95x10²² molecules Fe(H₂O)₂(SO₄)₃

There are 14 O atoms per Fe(H₂O)₂(SO₄)₃ molecule, so the answer is (7.95x10²² * 4) 3.18x10²³ atoms.

The atmosphere insulates the planet by trapping which of the following?
Solid particles

Thermal energy

Ice crystals

Wind

Answers

Answer:

The answer is thermal energy

Explanation:

A mole of carbon has the same number of atoms as a mole of beryllium.
O True
False

Answers

Answer:

False.

Explanation:

Carbon = 12

Beryllium = 9

good luck, i hope this helps :)

Which gas is given out during burning process

Answers

Answer:

Carbon dioxide

I hope it helps

#captainpower

pls make me brainliest

3. Which of these statements is false?
A. Electrons have a negative charge
B. Electrons have a mass of 1 amu
C. The nucleus of an atom is positively charged
D. The neutron is found in the nucleus of an atom

Answers

the answer is B. ......

it is also called solution

Answers

Explanation:

In chemistry, a solution is a special type of homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. ... The term "aqueous solution" is used when one of the solvents is water.

What determines the activity?

Answers

Answer:

what activity

Explanation:

what would happen to a piece of iron if it were placed close to this device

Answers

Answer: c) it moves toward a piece of iron

Explanation:

Shale is a sedimentary rock that can can be metamorphosed into slate by

Answers

The soft, clay-rich rock known as shale, when subjected to pressure becomes a harder rock called slate. ... Even coal can be metamorphosed; bituminous (soft) coal, a sedimentary rock, can be changed into anthracite, or hard coal.


How many carbon atoms are in 15.6 kg of acetone? acetone is ch3coch3. the density of acetone is 1.30 g/ml?

Answers

It’s acetone chemical 02.0

what did the law of octaves state about the elements​

Answers

Law of octaves states that when the elements are arranged in ascending order of atomic mass, every eighth element has comparable properties.

What are the characteristics of law of octaves ?

Features of law of octaves -:

Newland Octaves arranged the known 62 elements into 8 groups of 8 each. The elements were in increasing order of atomic weight.Every element shared properties with the 8th element after it.

Some limitations were made into this -:

It left no space for new elements to be discovered. It grouped some dissimilar elements together, e.g. halogens with metals. It worked well only up to Calcium.

Learn more about law of octaves ,here:

https://brainly.com/question/756068

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The law of octaves state about the elements​ that there must be 8 electrons in the outermost or valance shell of the electron to obtained the stability.

What is octaves rule?

when the elements are arranged in the increasing order of atomic mass, every eighth element has comparable properties and  that  was the first time an atomic number was introduced  to each element of the periodic table.

To become the stable according to rule element must complete it octave otherwise it cannot be considered the stable one.

Therefore, law of octaves state about the elements​ that there must be 8 electrons in the outermost or valance shell of the electron to obtained the stability.

Learn more about octave rule, here:

https://brainly.com/question/13935829

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What affects both deep water and surface currents in the ocean?

Answers

Answer:

These currents are on the ocean's surface and in its depths, flowing both locally and globally. Winds, water density, and tides all drive ocean currents. Coastal and sea floor features influence their location, direction, and speed. Earth's rotation results in the Coriolis effect which also influences ocean currents. -

Answer: The Coriolis effect

Explanation:

1. Which of the following best explains the motion of the box on the table?

Answers

Answer:

The box is at rest

Explanation:

not moving object

how many modern periodic table contains​

Answers

Answer:

118 elements in the periotic table

Explanation:

:)

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