Graphene is made of pure _______________.

Explanation:

If you know the frequency of the photon, you can calculate the wavelength using the equation λ=cν where c is the speed of light and ν is the frequency.

λ=cν

f=T^-1,f=1/7.81×1014s

c=3×10^8m/s

λ=3×10^8m/s×1/7.81.×1014s

λ=37881.94m

Answer:If we dissolve NaF in water, we get the following equilibrium:

text{F}^-(aq)+text{H}_2text{O}(l) rightleftarrows text{HF}(aq)+text{OH}^-(aq)

The pH of the resulting solution can be determined if the  K_b of the fluoride ion is known.

20.0 g of sodium fluoride is dissolve in enough water to make 500.0 mL of solution. Calculate the pH of the solution. The  K_b of the fluoride ion is 1.4 × 10 −11 .

Step 1: List the known values and plan the problem.

Known

mass NaF = 20.0 g

molar mass NaF = 41.99 g/mol

volume solution = 0.500 L

K_b of F – = 1.4 × 10 −11

Unknown

pH of solution = ?

The molarity of the F − solution can be calculated from the mass, molar mass, and solution volume. Since NaF completely dissociates, the molarity of the NaF is equal to the molarity of the F − ion. An ICE Table (below) can be used to calculate the concentration of OH − produced and then the pH of the solution.

Explanation:

Answer:

not sure if this is 100% correct but this is what i got first question: molarity=mol/L 5g*1mol/58.44g=5/58.44 =0.085558mol 4.8m=0.085558/L L=0.0178

jiujuan avatar

second question: pH = - log [H3O+] pH= -log [4.6*10^-9] = 8.33724216

Explanation:

Answer:

Explanation:

False. The greater the concentration, the lower the freezing point.

Answer:

The particles move very fast and collide into one another, causing them to diffuse, or spread out, until they are evenly distributed throughout the volume of the container. When more gas particles enter a container, there is less space for the particles to spread out, and they become compressed.

Explanation:

Answer:

these metals are stored in kerosene because kerosene contains no water and protects these metals from being exposed to any moisture in the air that would cause these metals to react, potentially violently.

Answer:

CH2

Explanation:

The empirical formula is the simplest formula of a chemical compound. It shows the ratio in which constituent atoms are combined in the compound.

To obtain the empirical formula, we divide the given mass of each element by the relative atomic mass of that element.

C- 36.0 g/12.0 g         H- 6.0g/1.0g

C- 3                             H-6

Divide through by the lowest ratio;

C-3/3                              H- 6/3

C-1                                  H-2

Hence the empirical formula of the compound is

CH2

5.6 atm is  the partial pressure of the rest of the gases in the container other than the oxygen.

Each gas in a mixture adds to the overall pressure of a mixture. This portion represents the pressure. The pressure a gas would have if it were in its own volume and at its own temperature is known as the partial pressure. According to Dalton's law, the pressure distribution of an ideal gas mixture is equal to the combined partial pressures of the component gases.

The study of partial pressure is significant in the domains of physics, chemistry, and biology. The partial pressure of oxygen or carbon dioxide in the blood is used to calculate blood levels of each substance. The overall pressure in a container is equal to the sum of the partial pressures. The remaining gases must make up the remaining 5.6 atm if the oxygen partial pressure equals 4.2 atm and the sun reaches 9.8 atm in pressure.

Therefore, 5.6 atm is  the partial pressure of the rest of the gases in the container other than the oxygen.

To know more about partial pressure, here:

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Answer:

the first on is Chromium(VI) peroxide or chromium oxide peroxide

the second on it Hydrogen Carbonate

Explanation:

I hope this helped ;)

Answer:

1.06 liters of gas are produced

Explanation:

Our reaction is:

CaCO₃(s) → CaO(s) + CO₂ (g)

This is the decomposition of calcium carbonate.

Ratio is 1:1:1

1 mol of carbonate can decompose to 1 mol of oxide and 1 mol of oxygen.

We convert mass to moles:

4.74 g . 1 mol /100.08g = 0.0474 moles

These are the moles of oxygen produced.

We know that 1 mol of any gas at STP is contained in 22.4L

0.0474 mol . 22.4L /mol = 1.06 L

Answer:

0.16 J/g℃

Explanation:

We have the following data:

heat = 1,200 J

mass of metal = m = 150 g

change in temperature = ΔT = 50.0℃

The heat absorbed is calculated by using the following equation:

heat = m x Cp x ΔT

So, we introduce the data in the equation to calculate the specific heat of the metal (Cp), as follows:

Cp = heat/(m x ΔT) = (1,200 J)/(150 g x 50.0℃) = 0.16 J/g℃

Answer:

Pressure will increase by the direct ratio of the volume change. Therefore, since volume changes from 145 to 80, pressure will go up by the ratio change 145÷80 times the original pressure 125 kPa. Sure, you can use the more complicated gas law equation PV = nRT but we are only varying volume so the question boils down to the change in one simple variable.

Putting them together we have: 145÷80 x 125 = 226.5625 or just 226 kPa since the accuracy of the figures and the equation are not great.

Answer:

you probably not Finn look at this from 1 week

Explanation:

sooo ug

Answer:

its the lunar and solar eclipse

Explanation:

the solar eclipse happens when the moon is in between the sun and earth

Answer:

hydrochloric acid

Explanation:

Zinc oxide will react with hydrochloric acid to form zinc chloride and water.

sulphuric acid

So to make zinc sulphate crystals you add granulated zinc to heated sulphuric acid

Answer:

53∘

plz mark me as brainliest.

Periodic table has been divided into three, one is metal, second is non metal and third metalloid. Therefore,  hydrogen is considered as non metal.

Metals are those elements which is hard, conduct electricity, ductile, lustrous and malleable.

Lets take property

1.Since metals have free electrons that's why they can conduct electricity

2. Since atoms in metals are very closely packed in a definite crystal so Aluminium is solid. It is not brittle that is it can not be broken down easily

3. It does not react with water.

4.It is denser than water hence it sink in water.

Since hydrogen has only 1 electron in its outermost shell, to complete its duet and gain stability, hydrogen has to gain 1 electron just like halogen. So, on this basis hydrogen is considered as non metal.

Therefore,  hydrogen is considered as non metal.

Learn more about the metals, here:

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Answer:

Because warm air is less dense

Explanation:

Answer:

When an organism dies, it is usually destroyed by other forms of life and by weathering processes. On rare occasions some body parts—particularly hard ones such as shells, teeth, or bones—are preserved by being buried in mud or protected in some other way from predators and weather. Eventually, they may become petrified and preserved indefinitely with the rocks in which they are embedded. Methods such as radiometric dating—measuring the amounts of natural radioactive atoms that remain in certain minerals to determine the elapsed time since they were constituted—make it possible to estimate the time period when the rocks, and the fossils associated with them.

Answer:

2.41 Litres

Explanation:

Using the combined gas law equation as follows;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (atm)

P2 = final pressure (atm)

V1 = initial volume (L)

V2 = final volume (L)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information provided in this question;

P1 = 1 atm

P2 = 0.65 atm

V1 = 1.75 liters

V2 = ?

T1 = 21°C = 21 + 273 = 294 K

T2 = -10°C = -10 + 273 = 263 K

Using P1V1/T1 = P2V2/T2

1 × 1.75/294 = 0.65 × V2/263

1.75/294 = 0.65V2/263

Cross multiply

294 × 0.65V2 = 1.75 × 263

191.1 V2 = 460.25

V2 = 460.25 ÷ 191.1

V2 = 2.41 L

Explanation:

                 Algae is a group of a photosynthetic eukaryotic organisms that plays a very important role on the ecosystem. It forms the lower base of the food chain and supports all the life forms of the ecosystem. It takes up water and carbon dioxide from the atmosphere to prepare food during the process of photosynthesis and maintains a balance in the ecosystem.

                In the context, if the algae disappears, the fish might die as the small fishes feeds on this algae. This is a concern as the algae is main component of food source and forms the base of the food chain. If there will be no algae there will be no life form on earth, as all species depend on each other to survive.

                  In order to prevent this from occurring, we must protect our algae. We must plant more trees, keep our water bodies healthy, we should not litter our ponds and lakes. We should also help these algae to grow and survive so that other life forms can feed them and thus maintain the ecosystem.

Answer:

λ = 2.94 m (in meters)

λ = 2.94 x 10⁹ nm (in nanometers)

λ = 2.94 x 10¹⁰ A (in angstrom)

Explanation:

The wavelength of the radio station can be given as follows:

[tex]\lambda = \frac{c}{f}\\[/tex]

where,

λ = wavelength = ?

f = frequency = 102 MHz = 1.02 x 10⁸ Hz

c = speed of light = 3 x 10⁸ m/s

Therefore,

[tex]\lambda = \frac{3\ x\ 10^8\ m/s}{1.02\ x\ 10^8\ Hz}[/tex]

λ = 2.94 m (in meters)

λ = (2.94 m)(10⁹nm / 1 m)

λ = 2.94 x 10⁹ nm (in nanometers)

λ = (2.94 m)(10¹⁰ A / 1 m)

λ = 2.94 x 10¹⁰ A (in angstrom)

Answer:

You transfer kinetic energy from you foot to the ball.

Explanation:

Energy cannot be created or destroyed.

Answer:

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Answer:

Explanation:

Answer:

hi jajsbbsjsmsksjsksksjsjdkkdkdndndnxjsjsksksksjsksmsnznnsnsnznsjsjshsjjajannananabababababajajajajajabananabbananajanabajajakmaka

Answer:

0.897 J/g.⁰C

Explanation:

Given the following data:

m = 170 g (mass)

ΔT = 20.0⁰C (change in temperature)

q = 3050 J (amount of heat)

The amount of heat (q) is calculated as follows:

q = m x Cp x ΔT

Thus, we introduce the data in the mathematical expression to calculate the specific heat (Cp):

Cp = q/(m x ΔT) = 3050 J/(170 g x 20.0⁰C) = 0.897 J/g.⁰C

Answer:

Speed is the rate of change of position expressed as distance travelled per unit of time .

Explanation: