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CHEMISTRY

Answer:

The oxidation number of metallic copper is zero. In its compounds, the most common oxidation number of Cu is +2. Less common is +1. Copper can also have oxidation numbers of +3 and +4

Explanation:

Answer: V₂ = 37.71mL

Explanation: To determine the new volume of Helium gas, use the Combined Gas Law, which states the following relationship among pressure, volume and temperature:

[tex]\frac{P_{1}V_{1}}{T_{1}} =\frac{P_{2}V_{2}}{T_{2}}[/tex]

where index 1 relates to the initial state of the gas and index 2 to the final state of the gas.

Temperature is in Kelvin, so:

T = °C + 273

For this situation, standard pressure is 1 atm. Temperatures will be:

T₁ = 20 + 273 = 293 K

T₂ = 91 + 273 = 364 K

Solving:

[tex]V_{2}=\frac{T_{2}P_{1}V_{1}}{P_{2}T_{1}}[/tex]

[tex]V_{2}=\frac{364*1*85}{2.8*293}[/tex]

[tex]V_{2}=\frac{30940}{820.4}[/tex]

[tex]V_{2}=[/tex] 37.71

The new volume of He gas is 37.71 mL.

Answer:

Speed

Explanation:

Motion can be represented by a distance-time graph, which plots distance on the y-axis and time on the x-axis. The slope of a distance-time graph represents speed. The steeper the slope is, the faster the speed.

Hope this helps!:)

The question is incomplete, the complete question is;

Suna passes an electric current through a sample of clear, colorless, and odorless liquid. As the experiment continues, bubbles form, and the volume of liquid decreases. Suna collects samples of two colorless, odorless gases that bubble out of the liquid. One of the gases burns. Neither the original liquid nor the other gas burns. Which is the best explanation of her results? The electric current changed some of the sample to gas even though the sample was not breaking down. Therefore, the original liquid is a compound. The electric current released a gas that was odorless and colorless, like the original sample. Therefore, the original liquid is an element. The sample was broken down by the electric current and formed a new substance that could burn. Therefore, the original liquid is a compound. The sample lost some of its volume, but the gas still had the same chemical makeup as the original sample. Therefore, the original liquid is an element.

Answer:

The sample was broken down by the electric current and formed a new substance that could burn. Therefore, the original liquid is a compound.

Explanation:

When electric current is passed through a compound, the compound may become broken down to release its constituents. We refer to this phenomenon as electrolysis. We can now say that the substance has been 'decomposed' electrolytically.

Since the original sample was decomposed to yield a gas that could burn and one that couldn't burn even though the original sample couldn't burn, then the original sample is a compound.

Answer:

barium and silicon has same valence electrons

Explanation:

barium-2,8,18,18,8,2

neon-2,8

silicon-2,8,2,2

carbon-2,4

Answer: both barium and silicone

Explanation:

it was an my exam

Answer:

Electrons are added to atomic orbitals in order from low energy bottom of the graph to high (top of the graph according to the Aufbau principle. Principle energy levels are color coded, while sublevels are grouped together and each circle represents an orbital capable of holding two electrons

Explanation:

Answer:

2.86g

Explanation:

Mass of HCl  = 2.87g

Mass of water  = 3.75g

Mass of NaCl  = 1.98g

Unknown:

Mass of NaOH reacted  = ?

Solution:

  The reaction expression is given as:

           HCl    +   NaOH   →   NaCl   +  H₂O

According to the law of conservation of mass, the mass of reactants and products must be the same.

   Mass of HCl   +   Mass of NaOH  = Mass of NaCl  +  Mass of H₂O

      2.87g + Mass of NaOH  = 1.98g + 3.75g

           Mass of NaOH  = 1.98g + 3.75g - 2.87g  = 2.86g

Answer:

1 = 7.5m/s and 2 = 8m/s

Explanation:

For question no. 1

Given

wavelength = 5 m

Frequency = 1.5 Hz

Velocity =?

We have the formula that

Velocity = wavelength * frequency

= 5 * 1.5

= 7.5 m/s

For question no. 2

Frequency = 2 Hz

Wavelength = 4 m

Velocity = ?

We have the formula that

Velocity = wavelength * frequency

= 4* 2

= 8 m/s

Hope it will help :)

Answer:

1. 7.5m/s

2. 8m/s

Explanation: velocity = Wavelength x Frequency so 5m*1.5Hz=7.5m/s and 2Hz*4m=8m/s

Answer:

A) The crust

hope this helps :)

Explanation:

Answer:

The coolest part in the diagram shown is A.) The Crust

Explanation:

This is because as more and more layers form, they soon harden because they are further away from the heat force, which would be the core.

Hope this helps. Sorry if I am wrong. ;-;

Answer:

Explanation:

(a) there are strong forces (of attraction) between the particles in a solid

accept molecules / atoms for particles throughout

accept bonds for forces

1

(holding) the particles close together

particles in a solid are less spread out is insufficient

1

or

(holding) the particles in a fixed pattern / positions

but in a gas the forces between the particles are negligible

accept very small / zero for negligible

accept bonds for forces

1

so the particles spread out (to fill their container)

accept particles are not close together

gas particles are not in a fixed position is insufficient

One kilogram of a gas has a much larger volume than one kilogram of a solid. In kinetic theory particles in a solid are less spread out but in gas the force between the particles are negligible.

The kinetic theory of matter states that all matter is made up of tiny particles which are constantly moving in a state of motion. All particles should posses energy.

Thus from above conclusion we can say that One kilogram of a gas has a much larger volume than one kilogram of a solid. In kinetic theory particles in a solid are less spread out but in gas the force between the particles are negligible.

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Answer:

No

Explanation:

The stronger the intermolecular forces the molecules tend to stay in the liquid phase. Compounds with weak intermolecular forces are more volatile and more molecules overcome those forces to pass to the gas phase.

Moles of Bromine produced = 9 moles

Given

9 moles of Chlorine gas

Word equation

Required

Moles of Chlorine produced

Solution

We change the word equation into a chemical equation (with a formula)

Aluminum bromide reacts with chlorine gas to produce Aluminum chloride and bromide gas

2AlBr₃+3Cl₂⇒2AlCl₃+3Br₂

moles Cl₂ = 9

Maybe you mean, how many moles of Bromine can we produce?

From equation, mol ratio Cl₂ : Br₂ = 3 : 3, so mol Br₂=mol Cl₂=9 moles

Answer:

61.5 dry quarts = 67.72509L

Explanation:

Answer:

Mathematics is used in Physical Science to calculate the measurements of objects and their characteristics, as well as to show the relationship between different functions and properties. Arithmetic, algebra and advanced mathematics may be used.

Explanation:

Answer:

Weigh the empty crucible, and then weigh into it between 2 g and 3 g of hydrated copper(II) sulphate. Record all weighings accurate to the nearest 0.01 g.

Support the crucible securely in the pipe-clay triangle on the tripod over the Bunsen burner.

Heat the crucible and contents, gently at first, over a medium Bunsen flame, so that the water of crystallisation is driven off steadily. The blue colour of the hydrated compound should gradually fade to the greyish-white of anhydrous copper(II) sulfate. Avoid over-heating, which may cause further decomposition, and stop heating immediately if the colour starts to blacken. If over-heated, toxic or corrosive fumes may be evolved. A total heating time of about 10 minutes should be enough.

Allow the crucible and contents to cool. The tongs may be used to move the hot crucible from the hot pipe-clay triangle onto the heat resistant mat where it should cool more rapidly.

Re-weigh the crucible and contents once cold.

Calculation:

Calculate the molar masses of H2O and CuSO4 (Relative atomic masses: H=1, O=16, S=32, Cu=64)

Calculate the mass of water driven off, and the mass of anhydrous copper(II) sulfate formed in your experiment

Calculate the number of moles of anhydrous copper(II) sulfate formed

Calculate the number of moles of water driven off

Calculate how many moles of water would have been driven off if 1 mole of anhydrous copper(II) sulfate had been formed

Write down the formula for hydrated copper(II) sulfate.

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Explanation:

Answer:

P₂ = 0.87 atm

Explanation:

Given data:

Initial pressure = 1.10 atm

Initial volume = 19.2 L

Final volume = 24.3 L

Final pressure = ?

Solution:

The given problem will be solved through the Boyle's law,

"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"

Mathematical expression:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = initial volume

P₂ = final pressure

V₂ = final volume  

Now we will put the values in formula,

P₁V₁ = P₂V₂

1.10 atm × 19.2 L = P₂ × 24.3 L

P₂ = 21.12 atm. L/ 24.3 L

P₂ = 0.87 atm

Answer:

202.5 K

Explanation:

Answer:

Gravity.

Explanation:

In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are;

1. Solid: it is the state of matter in which the physical substance has a definite shape and fixed volume but not compressible. Examples of solids are pen, screwdriver, television, car etc.

2. Liquid: it is the state of matter in which the physical substance can be poured and it takes the shape of its container. Also, liquids generally have a definite volume. Examples of liquids are urine, water, milk, blood etc.

3. Gas: it is the state of matter in which the physical substance has no definite shape or volume and as a result fills all available space. Also, gases are easily compressible and can flow. Examples of gases are hydrogen, oxygen, argon, nitrogen etc.

The attraction between all objects that have matter is generally referred to as gravity.

Generally, this force of attraction (gravity) attracts an object (body) towards another having mass, or towards the center of a planetary body such as earth.

Answer:

The answer to your question is D.

Explanation:

The latitudes near the equator receives the most direct solar energy.

Hope this helps :)

Answer:

Specific gravity compares the density of a substance to the density of air.

Specific gravity is compared the density of a substance to the density of water.

Specific Gravity is a dimensionless quantity that can be defined as the ratio of the density of a substance to the density of the water at a particular temperature.

The mathematical formula of the specific gravity can be written as:

Specific gravity = density of substance / density of water

The density of water at 4°C is used as a reference point as water has the highest density of 1000 kg/m³.  Specific gravity or relative gravity does not have any dimension as it is a dimensionless quantity.

Specific gravity is the ratio of a substance’s density to that of water at a specific temperature. The temperature plays an important role in determining the specific gravity of a substance.

Therefore, specific gravity is a characteristic of the substance at a particular temperature and pressure that also affects the specific gravity.

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Answer:

Percent composition tells you which types of atoms (elements) are present in a molecule and their levels. Percent composition can also tell you about the different elements present in an ionic compound as well.ion:

Answer:

Explanation:hey

Answer: B

Explanation:

Answer:

B. Both substances must be the same temperature.

Explanation:

Answer:

The rain filled the wagon with water meaning it gave the wagon more weight which made it hard to move.

Answer:

c

Explanation:

solid to gas directly

Answer:

5

Explanation:

The electrons in the outermost shell are the valence electrons. Since there are 5 electrons in the third energy level, there are 5 valence electrons.

Hope that helps.

Answer:

[tex]\pi[/tex] r²  x h

Explanation:

A can is cylindrical in nature. Using the formula of the volume of the can, we can find this unknown volume.

The volume of cylinder is given as:

   Volume of a cylinder  = Area x height

  Volume of  a cylinder = [tex]\pi[/tex] r²  x h

Therefore density of the can;

      Density  = [tex]\frac{mass}{volume}[/tex]