Which two observations are evidence that a chemical change is happening?
A. A yellow liquid forms as a yellow solid is slowly heated.
I B. Bubbles of gas are released when a solid is combined with a
liquid.
I c. Solid crystals form as the temperature of a liquid is lowered.
D. Light and heat are given off after a spark ignites a substance,

Answers

Answer 1
B. Bubbles are created whether using heat or not at inception of chemical change

Related Questions

Which of these is found in the energy levels of an atom?

Answers

Answer:

Electrons

Explanation:

Because the nucleas is In the middle and the Electrons surround it

what are the three molecules that are attached to the plasma membrane, and what are their roles/ functions?

Answers

Answer:

Ans:

*Carbohydrates

*Proteins

*Cholesterol

Explanation:

The plasma membrane is a structure that has several distinct roles in the cell

The plasma membrane is mainly composed of the phospholipid Bilayer, which is a layer of two sheets located in the internal and external parts. The Phospholipids are said to be Amphipathic because they have both properties of Hydrophobic and hydrophilic

*The Carbohydrate Molecules attach to the Plasma Membrane such as to the lipids and Proteins:

when They attach to the Proteins, they are known as glycoproteins, and they help in cell recognition, when they attach to the lipids, they are known as Glycolipids

*Protein Molecules play an important role in transport system such as Carrier Proteins

*Cholesterol Molecules help in balancing the Fluidity of the plasma membrane

hope this was of use

13. A natural flow of groundwater that has
reached the surface is a(n)
a. spring.
c. aquifer.
b. well.
d. travertine.

Answers

A natural flow of ground water that has reached surface level is call a spring.

Water moves underground downward and sideways, in great quantities, due to gravity and pressure.

A spring is the result of an aquifer being filled to the point that the water overflows onto the land surface. They come in different sizes, from intermittent seeps, which flow only after much rain, to huge pools flowing hundreds of millions of gallons daily.

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what do solid and gas-particle have in common? (not liquid )

Answers

Answer:

Solid, liquid, and gas are common states of matter. Because each particle is attached to several others, individual particles cannot move from one location to another, and the solid is rigid. A has a fixed volume but does not have a fixed shape. Liquids take on the shape of the container they are in.

Explanation:

sorry, this is what i think

Which example accurately describes a solution?

Answers

Typical examples of solutions are

Alcoholic beverage (ethanol in water)Gasoline

What is a solution?

A solution can be defined as a mixture (homogeneous) of two or more substances typically a solute in a solvent, the solvent is usually in greater quantity and the substance or substances present in lesser amounts are the solutes.

Other good examples of a solution

Common examples of solutions are  sugar in water and salt in water solutions, soda water,

Furthermore, solutions can be homogenous or heterogenous

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the mass number of an element whose atoms contain 18 protons, 22 neutrons and 18 electrons

Answers

Answer:

Argon has the chemical formula Ar. Argon has 18 protons and 22 neutrons in its nucleus giving it an Atomic Number of 18 and an atomic mass of 40. Argon is a Noble Gas. Argon is a gas at room temperature.

Explanation:

question: the diagram below shows the major parts of the digestive system.
what part of the digestive system is labeled by the number 1?
A.
small intestine
B.
esophagus
C.
stomach
D.
mouth

Answers

D . mouth bc the esophagus is like the throat

Answer:

I got it Right in Study Island

Explanation:

“Burning of fossil fuels causes pollution.” Suggest alternative methods by
which we can overcome this global issue in less than 250 words.

Answers

An alternative method by which we can overcome this global issue is by harnessing Solar energy.

Discussion:

Fossil fuels cause environmental pollution. This is because they are organic compounds and on combustion, they release air pollutants such as, Carbon monoxide.

As a panacea, the use of solar panels for harnessing Solar energy in a bid to replace energy from fossil fuels will prove to be am effective method by which we can overcome the global issue of pollution caused by burning of fossil fuels.

Solar energy is a clean source of energy as there's no release of harmful air pollutants.

Read more on fossil fuels:

https://brainly.com/question/14432674

Alternative method by which we can overcome this global issue is by

harnessing energy with less form of pollution. These include:

Solar energyHydropowerNuclear energy

Fossil fuel burning releases greenhouse gases such as Carbon dioxide,

nitrous oxide etc which causes pollution to the atmosphere.

It is best to adopt alternative methods mentioned above to ensure pollution

is reduced to the barest minimum. This helps to prevent ozone depletion and

global warming. It also reduces risks of respiratory diseases due to the

inhalation of the gases.

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Carbon-14 emits beta radiation and decays with a half life of 5730 years. Assume you start with 2.5x10^15 grams of Carbon-14, how many grams remain at
the end of 5 half lives?
A. 1.1x10^-10 g
B. 2.5x10^-10 g
C 1.3x10^-10 g
D. 5.0x10^-10 g

Answers

The amount remaining at the end of 5 half-lives is 7.81×10¹³ g

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

Half-life (t½) = 5730 yearsOriginal amount (N₀) = 2.5×10¹⁵ gNumber of half-lives (n) = 5Amount remaining (N) =?

The amount remaining can be obtained as follow:

N = 1/2ⁿ × N₀

N = 1/2⁵ × 2.5×10¹⁵

N = 1/32 × 2.5×10¹⁵

N = 0.03125 × 2.5×10¹⁵

N = 7.81×10¹³ g

Therefore, the amount remaining after 5 half-lives is 7.81×10¹³ g

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Which model of the atom is thought to be true?

A. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.
B. The nucleus is made of protons, electrons, and neutrons.
C. Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
D. The nucleus is made of electrons and protons.

Answers

Its A. Explanation:I just know

Helpppppppp plzzzzzz asaaaapppp

Answers

Answer:

Alright, the first thing we have to do is to balance the chemical equation

2Na3N -----> 6Na + 1N2

We have 60g of Na3N, we convert them into moles by dividing the mass of the compound by the molar mass.

Molar mass of Na3N = (22.98 x 3) + (14) = 82.94g/mol

  60          =  0.72341451651 moles of Na3N

82.94

Now because we did the balanced equation, we know the mole to mole ratio of Na3N to N2 would be 2:1, so in order to get the moles of N2 you have to divide the moles of Na3N by 2

0.72341451651 moles/2 = 0.361707258 moles of N2

Now that we have the moles of N2, we just have to determine the mass of it in grams. In order to do that, just multiply the moles by the molar mass of N2 (28g/mol)

0.361707258 x 28 = 10.13g of N2

Therefore the decomposition of 60g of Na3N would result in 10.13g of N2 (nitrogen gas)

Two gas jars are connected to each other, but they are separated by a closed valve. One gas jar contains oxygen, and the other contains hydrogen. What will happen when the valve is opened?

Answer Choices:

A. Oxygen and hydrogen molecules will mix because of random movement of their molecules.
B. Oxygen and hydrogen molecules will remain in separate jars because of different partial pressures.
C. Oxygen and hydrogen molecules will remain in separate jars because of different rates of expansion.
D. Oxygen and hydrogen molecules will mix because the molecules have a much lower volume than the volume of the jars.

Answers

When the valve is opened, oxygen and hydrogen molecules will mix because of random movement of their molecules.

What is diffusion?

Diffusion involves the movement of gas molecules from one region where they are in higher concentration to another region where they are in lower concentration.

When the valve is opened, oxygen and hydrogen molecules will mix because of random movement of their molecules.

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Answer:

Oxygen and hydrogen molecules will mix because of random movement of their molecules.

Explanation:

how many grams of baf2 are dissolved in 75.0 ml of a saturated solution of baf2? ksp = 1.00 x 10-6

Answers

Using the solubility product of the saturated solution, the mass of BaF2 dissolved is 0.083 g.

The equation of the reaction is obtained from;

BaF2(s) ⇄ Ba^+(aq) + F^-(aq)

The concentration of the substance can be obtained from the Ksp as follows;

Ksp = [Ba^2+] [2F^-]^2

Ksp = 4x^3

x = ∛Ksp/4

x = ∛ 1.00 x 10-6/4

x = 6.3  x 10^-3 M

Given that;

mass/molar mass = concentration x  volume

molar mass  = 175 g/mol

concentration  = 6.3  x 10^-3 M

volume = 75.0 ml or 0.075 L

Mass = ?

Mass  = concentration x  volume x molar mass

Mass  = 6.3  x 10^-3 M x  0.075 L x   175 g/mol

Mass = 0.083 g

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How does an introduced species affect an ecosystem? Give 2 examples of positive ways
and 2 examples of negative ways.

Answers

Answer:

1+ it can help create balance among the ecosystem, particularly by controlling invasive species

2+ can help restore native ecosystems on degraded land

1- can become an invasive species

2- can cause an imbalance among native species

Explanation:

Find the percent composition of OXYGEN in Manganese (III) nitrate, Mn(NO3)3.

Answers

Answer:

59.8%

Explanation:

First find the Mr of manganese (III) nitrate.

Mr of Mn(NO₃)₃ = 54.9 + (14 × 3) + (16 × 3 × 3) = 240.9

Since we have to find the percentage composition of oxygen, we need to find the Mr of oxygen in the compound, which is:

Mr of (O₃)₃ = (16 × 3) × 3 = 144

Now we can find percentage composition / percentage by mass of oxygen.

% composition = [tex]\frac{Mr\ of\ oxygen\ in\ compound}{Mr\ of\ compound}[/tex] × 100

% composition = [tex]\frac{144}{240.9}[/tex] × 100 = 59.776%

∴ % compostion of oxygen in maganese(III)nitrate is 59.8% (to 3 significant figures).

Which of the liquids will sink in milk?

Answers

Answer:

mercury 13.6 has a great density than milk

Write the scientific term "A number used by Bohr in the explanation of the spectrum of hydrogen atom and designated by the symbol (n) " ?​

Answers

Answer:

Quantum number

Explanation:

which statement describes how the binary ionic compound cacl2 is named?

Answers

Calcium Chloride because it is a type 1 so the the anion ends with -ide

how much evaporated milk equals 1 cup of whole milk?

Answers

Answer:

1/2 cup evaporated milk plus 1/2 cup water.

Explanation:

Which objects refract light? (Select all that apply.)
the human eye
contact lenses
a magnifying glass
concave mirrors

Answers

Concave mirrors, magnifying lens... sorry not sure about the rest
Magnifying glass and concave mirrors

look at attachment please help with it, will mark brainliest <3 BUT ONLY IF CORRECT ​

Answers

Answer = mass is constant

Mass is the measure of amount of matter in an object, it does not change.

Mass does not change with gravity, it is the weight that changes with gravity, as weight = mass x gravity.

What state of matter has a defined volume but undefined shape?

Question 6 options:

gases

liquids

solids and liquids

liquids and gases

Answers

Answer:

Liquids

Explanation:

They have a certain volume but they take the shape of their container

what happens when carbon dioxide gas is cooled to -78 degree Celsius​

Answers

Answer:

It will be solid

Explanation:

-78 C° is the freezing point of carbon dioxide, so at the temperature of -78 Celsius, the particles of carbon dioxide will come closer together and have about a fixed position to vibrate. The carbon dioxide will turn into solid. The solid form of carbon dioxide is also called dry ice.

(01.07 HC)

A student collected the data shown in the table below during an experiment.


Liquid Characteristics
Liquid Characteristics
Boiling Point Freezing Point Color Expansion per Degree Change in Temperature
Mercury 357 °C −39 °C shiny silver gray relatively lower
Alcohol 78 °C −115 °C colorless relatively higher


Based on the data, which of the following conclusions can be made about the use of mercury and alcohol thermometers?
A mercury thermometer can measure the freezing point of a liquid that freezes at −80 °C.
An alcohol thermometer can measure the boiling point of a liquid that boils at 80 °C.
A mercury thermometer is better to measure very small changes in temperature.
An alcohol thermometer is better to measure the boiling points of colorless liquids.

Answers

Answer: a mercury thermometer is better to measure very small changes in temperature

Explanation:

i took the test and got it right

Answer:

the answer is C, a mercury thermometer is better to measure very small changes in temperature.

Explanation:

i just took the test and it was correct :)

Can someone help?

Name the compound:

Answers

CH=benzene

Why?

benzene is represented by the empirical formula CH, which indicates that a typical sample of the compound contains one atom of carbon (C) to one atom of hydrogen (H).

----(Is this what you meant???)

Describe how this instrument works.
(legit this is 100pts so uhh help)
Operation

Answers

Answer:

This is a reflector telescope and  in which it captures different wavelengths of light and it hits one mirror, bounces back and hits another and then is shown through the eyepiece. It captures all of the visible spectrum and some areas above and below it. These telescopes are better for seeing big picture and not the fine details in planets surfaces.

Hope this helps!

Explanation:

Answer:

This is a reflector telescope and  in which it captures different wavelengths of light and it hits one mirror, bounces back and hits another and then is shown through the eyepiece. It captures all of the visible spectrum and some areas above and below it. These telescopes are better for seeing big picture and not the fine details in planets surfaces.

Hope this helps!

Explanation:

Which shows the weight of an atom?

atomic mass

atomic number

chemical symbol

none of the above

Answers

Answer:

The atomic mass

Explanation:

Answer: atomic mass

                                                                                                                                               

which describes an attribute of nonrenewable resources

Answers

Answer:

atributes  of nonrenewable recources are things you cant re use after 1 use like gas

Explanation:

Answer: the answer is b. Are unlimited

Explanation:

I need help!!!!!!!!!!!!!!!

Answers

Answer:

I think the answer is A.

Explanation:

hope this helps.

a scientist finds an organism that has a single cell without a nucleus.This organism was found in pond water.In which KINGDOM douse it belong?if you can explain

Answers

Archaea (Archaeon ): Single-celled microorganisms without nuclei and with membranes different from all other organisms. Once thought to be bacteria.

Unicellular organism

-A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms.

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