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Answer:

A then C

Explanation:

Answer:

a,c

Explanation:

When an electron moves from n = 2 to n = 1, it emits a photon of ultraviolet light.

During transition from n=2 to n=1 in a hydrogen atom, the electron emits energy in the form of photon. We know that when electron absorb energy, it moves from lower level to higher level and vice versa.

So we can conclude that when an electron moves from n = 2 to n = 1, it emits a photon of ultraviolet light.

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Answer:

Growing population

The worlds developing regions will see 1.2 billion people added, a 20.7% increase; while the population of developed countries will increase a mere 3.3% adding 41 million to the current 1.3 billion people.

The pressure of a 5.00 L flask at 25˚ C that contains 0.200 mol of Cl2 is 0.98atm.

The pressure of a gas can be calculated by using the following expression:

PV = nRT

Where;

P × 5 = 0.2 × 0.0821 × 298

5P = 4.893

P = 4.893 ÷ 5

P = 0.98atm

Therefore, the pressure of a 5.00 L flask at 25˚ C that contains 0.200 mol of Cl2 is 0.98atm.

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Answer:

Your answer would be:
0.98atm.

Explanation:

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The interaction which will occur when the non sticky tape pieces are turned towards each other is attraction.

This involves the coming together of objects as a result of a force. When non-sticky sides of the tape are brought towards each other attraction takes place due to the sticky content.

This however wears off after some time thereby making it the most appropriate choice.

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Answer:

Explanation:

NH4NO3(s) N2O(g) + 2H2O(g) What is the total volume of gases produced at 546 K and 1.00 atm pressure when 240 g of ammonium nitrate undergoes the above decomposition reaction? A) 9 × 22.4 L B) 3 × 22.4 L C) 12 × 22.4 L D) 18 × 22.4 L E) 6 × 22.4 L

Answer: 0.109 mol

Explanation:

Balanced chemical equation:

3 Na(s) + AlCl3(aq) --> 3 NaCl(aq) + Al(s)

3 moles of sodium metal react with 1 mole of aluminum chloride to produce 3 moles of aluminum chloride and 1 mole of solid aluminum

Molar mass of Na = 22.99 g/mol

Mass(Na) = 7.5 g

Find number of moles of Na:

n = mass of Na/molar mass of Na

=(7.5 g)/(22.99 g/mol)

= 0.3262 mol

Molar mass of AlCl3,

MM = 1*MM(Al) + 3*MM(Cl)

= 1*26.98 + 3*35.45

= 133.33 g/mol

Mass(AlCl3) = 20.0 g

Find number of moles of AlCl3,

n = mass of AlCl3/molar mass of AlCl3

=(20 g)/(1.333*10^2 g/mol)

= 0.15 mol

Balanced chemical equation is:

3 Na + AlCl3 ---> Al + 3 NaCl

3 mol of Na reacts with 1 mol of AlCl3

for 0.3262 mol of Na, 0.1087 mol of AlCl3 is required

But we have 0.15 mol of AlCl3

So, Na is the limiting reagent and we will use it in our further calculations.

According to balanced equation:

mol of Al formed = (1/3) * moles of Na

= (1/3)*0.3262

= 0.1087 mol

Answer: 0.109 mol of aluminum will precipitate out as a result of the reaction

If 0.380 mol of barium nitrate is allowed to react with an excess of phosphoric acid, 0.127 moles of barium phosphate could be formed.

The number of moles of a compound can be calculated stoichiometrically as follows:

Based on this question, the following chemical equation is given:

Ba (NO3)2+ H3PO4 → Ba3(PO4)2+ HNO3

The balanced equation is as follows:

3Ba(NO3)2 + 2H3PO4 → Ba3(PO4)2 + 6HNO3

3 moles of barium nitrate produces 1 mole of barium phosphate

Therefore, 0.380 moles of barium nitrate will produce 0.380/3 = 0.127moles of barium phosphate.

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Answer: The gas generated by two antacid tablets has a smaller volume.

Explanation:

Since the antiacid is the limiting reagent, we know that the more tablets there are, the more gas there will be.

This means that there will be more gas generated by the four antiacid tablets when compared to the two antiacid tablets, which gives us that the gas generated by the two antiacid tablets has a smaller volume.

The name of the covalent compound NH3 O2 is dihydroxylamine.

According to the task content;

On this note, the compound possesses 2 oxygen atoms, 3 Hydrogen atoms and 1 Nitrogen atom. Hence, the name of the covalent compound is Dihydroxylamine.

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Answer:

4.002602

Explanation:

the average that reflects the typical ratio of natural abundances of its isotopes.

The weight of 5 helium atoms in grams is 20.01301 grams.

Atoms are defined as the smallest unit into which matter can divided without the release of electrically charged particles.

It is also defined as a building block of matter and were discovered after big bang theory.  It is a fundamental piece of matter.

The weight of 1 helium atom = 4.002602 g

So, the weight of 5 helium atom = 4.002602 x 5

                                                      = 20.01301 g

Thus, the weight of 5 helium atoms in grams is 20.01301 grams.

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As the name implies, a secondary standard is used by standard laboratories, which include companies involved in the preparation of reagents and kits, as well as laboratories responsible to produce quality control material for use by other laboratories. They use the primary standard as the primary calibrator or primary reference material, and they calibrate their instruments against it. Smaller labs use secondary standards to calibrate control material for analysis of unknown concentrations. For smaller labs, secondary standard serves as an external quality control. As a result, it is essential that the secondary standard be standardized against the primary standard before it can be applied.

I hope this helps you

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Answer:

pbo2+cl-=clo-+pb(oh)2

Explanation:

balance by ion electron

Answer:

.0796  mole

Explanation:

Al2 (SO3)3      add the molecular weights

2 * Al = 2 * 26.982  +  

 3 * S  = 3 * 32.06   +

   9 * O  = 6 * 15.999      = 294.135  gm   per mole

Now... you have   23.4 grams of this substance

  23.4/294.135 = .0796 mole

EDITED !

1.06g

Please refer to the image attached.

You first find the number of moles (n) for KClO3 as you have been given the mass. So n = mass/Mr gives you the moles that is 0.022 mol

Next you use the ratio 2:3 as per the equation where it's 2KClO3 ---> 3O2 so you just cross multiply and get the moles for oxygen.

Now that you know the number of moles for oxygen, you can use the same moles equation that you used earlier to find the mass. mass=n×Mr and so you get the answer as 1.06g of oxygen.

Answer:

Metals tend to lose electrons in chemical reactions, as indicated by their low ionization energies. Within a compound, metal atoms have relatively low attraction for electrons, as indicated by their low electronegativities.

Example:-

We cannot pull back the reaction to get wax back .

Answer:

Explanation:

The permanent change in which a new substance is formed is called a chemical reaction.

For example:

i)Burning of wood

ii)Cooking rice

iii)Forming curd from milk

The burning of wood is a chemical reaction because it is a permanent change and it cannot be reversed. Once it is done, it is over it can't be done again. And in the case of example iii, the milk turns into curd by chemical reaction. A new substance i.e curd is formed from the milk.

Hope you understood!

Answer:

Explanation:

Calculate the pOH for a solution that has a hydroxide ion, (OH-) concentration of 5.02 X 10-4 M.

Calculate the pH.

Note: the answers should have three significant figures

Hey dear,

Benzene is a 6-C cyclic structure with alternate double bonds.

● Reactions -

1) Benzene to cyclohexane -

Benzene can be reduced to cyclohexane with

the help of Ni/H2. C6H6 + 3H2 --> C6H12

All 3 double bonds in ring are reduced here.

2) Benzene to benzoquinone - Benzene can be oxidized to benzoquinone with

the help of acidic K2Cr207. C6H6 +3[O] --> C6H4O2 + H2O

Only 1 double bond is lost in this reaction.

Hope this helps you.

The maximum safe operating temperature for this reaction is equal to 895°C.

Given the following data:

Scientific data:

Radius, r = [tex]\frac{width}{2} =\frac{22}{2} =11\;cm[/tex]

First of all, we would determine the volume of the stainless-steel cylinder by using this formula:

[tex]V=\pi r^2 h\\\\V = 3.142 \times 11^2 \times 26.4\\\\[/tex]

Volume, V = 10,036.81 [tex]cm^3[/tex].

In liters, we have:

Volume, V = 10.04 Liters.

Next, we would determine the number of moles of dinitrogen monoxide ([tex]N_2F_2[/tex]) gas:

[tex]Number \;of \;moles = \frac {mass}{molar\;mass}\\\\Number \;of \;moles = \frac {537}{66}[/tex]

Number of moles = 8.136 moles.

Now, we can solve for the maximum safe operating temperature by applying the ideal gas equation:

[tex]PV=nRT\\\\T=\frac{PV}{nR} \\\\T=\frac{6.30 \times 10^3 \times 10.04}{8.136 \times 8.314}\\\\T=\frac{60541.2}{67.6427}[/tex]

T = 895.02 ≈ 895°C.

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Answer:

A

Explanation:

the enzyme is substrate specifix coz of this trait

Answer: B Hope this helps :)

One material property that is widely used and recognized is the strength of a material. But what does the word "strength" mean? "Strength" can have many meanings, so let us take a closer look at what is meant by the strength of a material. We will look at a very easy experiment that provides lots of information about the strength or the mechanical behavior of a material, called the tensile test.

The basic idea of a tensile test is to place a sample of a material between two fixtures called "grips" which clamp the material. The material has known dimensions, like length and cross-sectional area. We then begin to apply weight to the material gripped at one end while the other end is fixed. We keep increasing the weight (often called the load or force) while at the same time measuring the change in length of the sample.

Explanation:

Answer:

Xenon hexafluoride's molar mass is about 245.28 g/mol
Formula mass is about 245.28 u.

Explanation:

So we want to find the formula mass of the XeF6 and there is a special formula for that.

You have to multiply the number of each element in XeF6 by the element's atomic mass.

The atomic mass of Xe is 131.293, and F's atomic mass is multiplied by 6, due to the 6 at the bottom. F's atomic mass is 18.998403, so we multiply the atomic number by 6, which would equal 113.990418. Round if you want, but it would equal mostly the same thing. Add it up to get ≈245.28, which is the same thing.

Therefore the formula mass of XeF6 is 245.28 u.

Answer:

Calcium chlorate | Ca(ClO3)2 - PubChem.

Explanation:

Answer:

digital signal

Answer:

Its made of numbers

Explanation:

did the assignment, hope this helps :]

If 30 grams of KCl is dissolved at 10°C, 14 g of KCl should be added to make a saturated solution at 60 °C.

A saturated solution is a solution in which there is so much solute that if there was any more, it would not dissolve. Its concentration is the same as the solubility at that temperature.

At 10 °C, the solubility is 31.2 g KCl/100 g H₂O.

30 g KCl × 100 g H₂O/31.2 g KCl = 96 g H₂O

At 60 °C, the solubility is 45.8 g KCl/100 g H₂O.

96 g H₂O × 45.8 g KCl/100 g H₂O = 44 g KCl

44 g - 30 g = 14 g

If 30 grams of KCl is dissolved at 10°C, 14 g of KCl should be added to make a saturated solution at 60 °C.

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Answer:

chemical equilibrium, condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs. A reversible chemical reaction is one in which the products, as soon as they formed, react to produce the original reactants.

Explanation:

chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.

Answer:

A

Explanation:

iron, cobalt and nickel are all transition metals