How many moles are 4.20 * 10 ^ 25 atoms of Ca?

Answer:A

Explanation:

1. [tex]^{222}Rn_{86}[/tex] → [tex]^{218}Po_{84} + ^{4}He_{2}[/tex]

What is a spontaneous decay?

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Answer:

1. Washing dishes and cooking

2. Water is used as a solvent in the manufacture of beverages and it is also largely used in agriculture.

3. Water conservation is the action of using water wisely and not wasting it.

4. i) Wash dishes in a tub of water instead of under a running tap.

ii) Use a pail of water to wash the car instead of spraying water from a hose.

iii) Make sure that there are no leaking or broken taps and pipes.

Answer:

Washing dishes and cooking

2. Water is used as a solvent in the manufacture of beverages and it is also largely used in agriculture.

3. Water conservation is the action of using water wisely and not wasting it.

4. i) Wash dishes in a tub of water instead of under a running tap.

ii) Use a pail of water to wash the car instead of spraying water from a hose.

iii) Make sure that there are no leaking or broken taps and pipes.

Explanation:

Answer:

c. The N2 molecules collide more frequently with the walls of the flask than do the Ar atoms.

Explanation:

The statements are:

a. There are more molecules of N2 present than atoms of Ar. FALSE. Because 1 mol of molecules of N2 = 28g and 1 mol of molecules of Ar = 40g. As there are equal MASSES, you will have more molecules of N2 than Ar molecules

b. The pressure is greater in the Ar flask. FALSE

Because pressure is directly proportional to amount of molecules. As molecules N2 > Molecules Ar. The pressure is greater in N2 flask

c. The N2 molecules collide more frequently with the walls of the flask than do the Ar atoms. TRUE

The collision probability of N2 is higher because there are more molecules presents

Answer:

1. Kc = [NO]⁴ [H₂O]⁶ / [NH₃]⁴ [O₂]⁵

2. Kc = [I₂]²

3. Kc = 1/[NH₃] [HCl]

Explanation:

The equilibrium constant (Kc) is equal to the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactant raised to their stoichiometric coefficients. It only includes gases and aqueous species.

1. 4 NH₃(g) + 5 O₂(g) ↔ 4 NO(g) + 6 H₂O(g)

Kc = [NO]⁴ [H₂O]⁶ / [NH₃]⁴ [O₂]⁵

2. ZrI₄(s) ↔ Zr(s) + 2 I₂(g)

Kc = [I₂]²

3. NH₃(g) + HCl(g) ↔ NH₄Cl(s)

Kc = 1/[NH₃] [HCl]

Answer:

1. Ions are either negatively or positively charged species in which the number of electrons and protons are not equal.

2. The chemical bond that arises due to the sharing of electrons is termed a covalent bond.

3. The positively charged ions are called cations, which comprise more protons than electrons.

4. An example of a polyatomic anion is the hydroxide anion.

5. The system of assigning an unambiguous name to a compound is called nomenclature.

Answer: 63.96%.

Explanation:

In 111g of Calcium chloride, there is 40g of Calcium and 71g of Chlorine. Percentage Composition of Chlorine is 63.96%.

Hope This Helps!

Answer:

The balanced equation will be your greatest asset in Solving this.

The Balanced Equation is

3Cl2 + 8NH3---> N2 + 6NH4Cl

So

From this reaction...

3 moles of NH3 is required to produce 6 moles of NH4Cl

Now the question asked.... How Many Moles of NH3 will be needed to produce 12moles of NH4Cl?...

The answer is simply 6moles of NH3.

Why?

Since 3moles of NH3 produce 6 moles of NH4Cl

It makes sense that

6moles of NH3 will produce 12moles of NH4Cl.

Its a simple Ratio.

Hope this helps...

I'm Open to questions if you have any.

Have a great Day!

Answer:buckled railroad tracks on a hot day

Explanation: i just did it

Answer:

589 torr or mmHg.

Explanation:

We know that 1 atmospheric pressure is equal to 760 torr or 760 mmHg so calculate 0.775 atm pressure in term of mmHg and torr. We perform the following steps which is

1 atm -------- 760 torr or mmHg

0.775 atm ------- X

By cross multiplication we get

X = 760 x 0.775

X = 589 torr or mmHg

So we can conclude that if 0.775 atm is equals to 589 torr.

Answer:

It's 23.14 percent

Explanation:

First, the mass of all the elements are:

N = 14

O = 16

Fe = 56

In this molecule you have 3 atoms of N, and 9 atoms of O, so:

3•14 = 42

16•9 = 144

The whole mass of the molecule is:

56 + 42 + 144 = 242

242/100 = 2.42, so 1% is 2.42

56/2.42 = 23.14%

Electron configurations

Valence electrons are electrons used in forming bonds and are in the outer shell of an element.  

The bond that occurs can be either an ionic bond or a covalent bond  

Valence electron determination using electron configurations.  

The main group elements usually have valence electron configurations in the s and p subshells  

While the transition elements in the subshells (n-1) d  

Further explanation

The location of the elemental groups in the periodic system is determined by the number of valence electrons filling the last sub-shell  

The period of an element is determined from the valence shell (the biggest main quantum number (n) )

In an atom, there are levels of energy in the shell and subshell  

This energy level is expressed in the form of electron configurations.  

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d, and f. The maximum number of electrons for each subshell is  

s: 2 electrons  

p: 6 electrons  

d: 10 electrons and  

f: 14 electrons  

Charging electrons in the subshell uses the following sequence:  

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.  

Answer:

70.6 %

Explanation:

First step, we define the reaction:

2P + 3Br₂  →  2PBr₃

We determine the moles of reactant:

35 g . 1mol / 159.8 g = 0.219 moles

We assume, the P is in excess, so the bromine is the limiting reagent.

3 moles of Br₂ can produce 2 moles of phophorous tribromide

Then, 0.219 moles may produce (0.219 . 2) /3 = 0.146 moles of PBr₃

We convert moles to mass:

0.146 mol .  270.67 g /mol = 39.5 g

That's the 100 % yield reaction, also called theoretical yield. The way to determine the % yield is:

(Yield produced / Thoeretical yield) . 100

(27.9 / 39.5) . 100 = 70.6 %

Answer:

7 is the mass number of li and 3 is the atomic number

a 3

b 7

c 3

d 4

Answer:

40

Explanation:

because the atomic number is how many electrons

Answer:

They are compounds.

Explanation:

..........

Answer:

compounds!!

Explanation:

...........

Answer: The pH of the solution is 2.74.

Explanation:

To calculate the pH of the acidic buffer, the equation for Henderson-Hasselbalch is used:

[tex]pH=pK_a+\log (\frac{\text{[conjugate base]}}{\text{[acid]}})[/tex]         .......(1)

The power of the acid dissociation constant is the negative logarithm of the acid dissociation constant. The equation for it is:

[tex]pK_a=-log K_a[/tex]        ......(2)

The chemical equation for the reaction of acetic acid and NaOH follows:

[tex]CH_3COOH+NaOH\rightleftharpoons CH_3COONa+H-2O[/tex]

Given values:

[tex]K_a=1.8\times 10^{-5}[/tex]

Putting values in equation 2:

[tex]pK_a=-log (1.8\times 10^{-5})\\\\pK_a=4.74[/tex]

We are given:

[tex]CH_3COOH[/tex] = 0.1 M

[tex]CH_3COONa[/tex] = 0.001 M

Plugging values in equation 1:

[tex]pH=4.74+\log (\frac{0.001}{0.1})\\\\pH=4.74-2\\\\pH=2.74[/tex]

Hence, the pH of the solution is 2.74.

Answer:

I say the correct answers are primary and secondary and teriary.

Explanation:

I say you are right!!

above because its above

Answer:

d

Explanation:did test

Answer:

Mg + 2H₂O —> Mg(OH)₂ + H₂

Explanation:

Mg + H₂O —> Mg(OH)₂ + H₂

The above equation can be balance as illustrated below:

Mg + H₂O —> Mg(OH)₂ + H₂

There are 2 atoms of H on the left side and a total of 4 atoms on the right side. It can be balance by writing 2 before H₂O as shown below:

Mg + 2H₂O —> Mg(OH)₂ + H₂

Now, the equation is balanced

****Check***

Element >>>>> Reactant >>>> Product

Mg >>>>>>>>>> 1 >>>>>>>>>>> 1

H >>>>>>>>>>> 4 >>>>>>>>>>> 4

O >>>>>>>>>>> 2 >>>>>>>>>>> 2

The balanced equation of Mg + H2O = Mg(OH)2 + H2​ is given as

Mg + 2H₂O —> Mg(OH)₂ + H₂

Generally, the equation for the Chemical equation  is mathematically given as

Mg + H₂O —> Mg(OH)₂ + H₂

Therefore, We se that  we have on the LHS

Mg=1

H=2

O=1

and on The RHS

Mg=1

H=4

O=2

Therefore to balance, we add 2 to H and 1 to O giving

Mg + 2H₂O —> Mg(OH)₂ + H₂

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Answer:

Number of moles  of sodium dissolved =  6.0 *10^23

Explanation:

The image for the question is attached

Solution

a) Total 181 ions of Na are dissolved

b)

The number of moles of sodium dissolved = 181/6.023 *10^23

Number of moles  of sodium dissolved = 5.987 * 10^23

Number of moles  of sodium dissolved =  6.0 *10^23

1. You didn't post the question to Number 1.

2.

10% means There's 10g in 100ml of this solution.

This is the weight/volume(w/v) expression of concentration.

So

We have Mass =10g

volume =100ml

Molarity = Moles of solute/volume of solution(in LITRES)

Moles=Mass/Molar mass

Molar mass of NaOH=40g/mol

Mole=10/40

=0.25mole

Volume =100ml =0.1Litres

MOLARITY=0.25/0.1 =

=2.5M

OPTION B.

3. NOTE: THE MOLARITY AND NORMALITY OF NAOH AND HCL ARE THE SAME(This doesn't happen for all compounds tho)

So We can take 2.5N(Normality) of NaOH to be 2.5M(Molarity) NaOH

I think you forgot to write the Normality of the second one. I'll take it to be 1N. Maybe you can then Input supposed value when you're solving on your own

So

1N HCl is same as 1M HCL

We were given their respective volumes

2.5M NaOH can also be written as 2.5mole/volume(in Liters)

The volume of NaOH =10ml or 0.01L

Moles = 2.5mole/L x 0.01L

You notice that Liters on top and bottom cancels out... leaving the moles

So

Mole=0.01x2.5 = 0.025moles of NaOH

we're gonna do the same for 1N HCl in 20ml(0.02L)

So

Mole = 1 x 0.02 =0.02moles

Total Mole = 0.02 + 0.025 =0.045moles

The Final Volume is 100ml as stated in the question. It was diluted to 100ml or 0.1L

So

Final Concentration In Molarity

= Total Moles/Volume in L

=0.045/0.1

=0.45M.

Answer:

Place a glass rod in the solution, if the crystallisation point has been reached, you should notice small crystals formed on it.

Answer: There are 0.0637 moles present in 85.0 mL of 0.750 M KOH.

Explanation:

Given: Volume = 85.0 mL (1 mL = 0.001 L) = 0.085 L

Molarity = 0.750 M

It is known that molarity is the number of moles of solute present in liter of a solution.

Therefore, moles present in given solution are calculated as follows.

[tex]Molarity = \frac{moles}{Volume (in L)}\\0.750 M = \frac{moles}{0.085 L}\\moles = 0.0637 mol[/tex]

Thus, we can conclude that there are 0.0637 moles present in 85.0 mL of 0.750 M KOH.

Answer:

2 mL.

Explanation:

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

Volume of water = 8 mL

Volume of water + solid = 10 mL

Volume of solid =?

The volume of the solid can be obtained as follow:

Volume of solid = (Volume of water + solid) – (Volume of water)

Volume of solid = 10 – 8

Volume of solid = 2 mL

Therefore, the volume of the solid is 2 mL

Answer:

Volume = 4614 m³

Explanation:

The volume of a pyramide is given by the following formula:

We are already given all the required information to calculate the volume by inputting the data:

The pyramid's volume is 4614 cubic meters.

Peptide is the name of the molecule formed when two amino acids join together. Therefore, the correct option is option A.

Short strands of amino acids connected by peptide bonds are called peptidides. A polypeptide is a peptide chain that is longer, continuous, and unbranched. Proteins are polypeptides with a molecular weight of 10,000 Dalton or higher. Oligopeptides, which comprise dipeptides, tripeptides, and tetrapeptides, are chains of fewer than twenty amino acids.

Peptides, along with nucleic acids, oligosaccharides, carbohydrates, and others, belong to the vast chemical families of biological polymers or oligomers. Proteins are made up of one or even more polypeptides structured in a biologically useful manner. They are frequently coupled to other proteins, other macromolecules like DNA or RNA, or ligands like coenzymes and cofactors. Peptide is the name of the molecule formed when two amino acids join together.

Therefore, the correct option is option A.

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Answer:

Suppose you added some solid NaCl to a saturated solution of NaCl at 20℃ and warmed the mixture to 40℃. What would happen to the added NaCl?

Explanation:

can you help with this one

1- Topsoil

2- Bedrock

3- Humus

4- Loam

5- Acyl, Clay, or Lacy

Well that was fun :)

Answer:

Explanation:

1. TOPSOIL

2. BEDROCK