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,

Answer:

The atomic mass

Explanation:

Answer: atomic mass

Answer:

I think the answer is A.

Explanation:

hope this helps.

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.

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

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:

Its A. Explanation:I just know

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

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:

Answer:

Electrons

Explanation:

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

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)

Answer:

Quantum number

Explanation:

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:

Answer:

mercury 13.6 has a great density than milk

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

Typical examples of solutions are

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.

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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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 :)

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).

Answer:

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

Explanation:

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:

Answer:

I got it Right in Study Island

Explanation:

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:

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.

Answer:

Liquids

Explanation:

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

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.

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

harnessing energy with less form of pollution. These include:

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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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:

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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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???)

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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