what is the atomic number of oxygen

Answer:

When there is no spark from the reaction

Explanation:

The reaction between the acid and the magnesium metal goes into completion when there is no more spark from the magnesium. Also, the magnesium would have totally disappeared into solution.

These physical observation marks the end of the reaction.

When Mg reacts with HCl hydrogen bubbles are released. The completion of the given reaction can be determined by the presence of bubbles above the HCl.

[tex]\bold {Mg+ 2HCl\rightarrow MgCl_2 + H_2}[/tex]

In this reaction, Mg reacts with 2 moles of HCl to form 1 mole of Magnesium chloride and release hydrogen gas.

During reaction,

Therefore, the completion of the given reaction can be determined by the presence of bubbles above the HCl.

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Answer:

(a) 6332.812 N (b) 1469.59  pounds.

Explanation:

Given that,

The surface area of the top of yu head is 25 cm x 25 cm

Area = 625 cm² = 0.0625 m²

Atmospheric pressure on it is 101325 Pa.

(a) Pressure acting on an object is given by force acting per unit area. It can be written as :

[tex]P=\dfrac{F}{A}\\\\F=PA\\\\F=101325\ Pa\times 0.0625\ m^2\\\\F=6332.812\ N[/tex]

6332.812 N of force is acting on your head at sea level.

(b) If area, A = 100 in²

We know that,

1 atm = 14.6959 pounds/in²

[tex]P=\dfrac{F}{A}\\\\F=PA\\\\F=14.6959 \ \text{Pounds}/in^2\times 100\ in^2\\\\F=1469.59\ \text{pounds}[/tex]

So, the force is 1469.59  pounds.

A. The force required to push your head at sea level is 6332.8125 N

B. The force in pound is 1469.59 lb

A. Determination of the force required at sea level.

Pressure (P) = 101325 Nm²

Area (A) = 25 cm × 25 cm = 0.25 m × 0.25 m = 0.0625 m²

P = F / A

Cross multiply

F = PA

F = 101325 × 0.0625

Therefore, the force required to push your head at sea level is 6332.8125 N

B. Determination of the force in pounds

Area (A) = 100 in²

Pressure (P) = 14.6959 pound / in²

F = PA

F = 14.6959 × 100

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Answer:

E = 5×10⁻¹⁹ J

Explanation:

Given data:

Wavelength = 400 nm (400×10⁻⁹ m)

Energy of wave = ?

Solution:

Formula:

E = h c/λ

c = 3×10⁸ m/s

h = 6.63×10⁻³⁴ Js

Now we will put the values in formula.

E = 6.63×10⁻³⁴ Js × 3×10⁸ m/s /400×10⁻⁹ m

E = 19.89×10⁻²⁶ J.m / 400×10⁻⁹ m

E = 0.05×10⁻¹⁷ J

E = 5×10⁻¹⁹ J

Answer:

Titration is a technique to determine the concentration of an unknown solution. As illustrated in the titration setup above, a solution of known concentration (titrant) is used to determine the concentration of an unknown solution (titrand or analyte).

Typically, the titrant (the solution of known concentration) is added through a burette to a known volume of the analyte (the solution of unknown concentration) until the reaction is complete. Knowing the volume of titrant added allows us to determine the concentration of the unknown analyte. Often, an indicator is used to signal the end of the reaction, the endpoint. Titrant and analyte is a pair of acid and base. Acid-base titrations are monitored by the change of pH as titration progresses.

Let us be clear about some terminologies before we get into the discussion of titration curves.

Complete Question

Calculate the pH during the titration of 20.00 mL of 0.1000 M trimethylamine, (CH3)3N(aq), with 0.2000 M HClO4(aq) after 9.48 mL of the acid have been added.Kb of trimethylamine = 6.5 x 10-5.

Answer:

The pH is  [tex]pH = 9.84[/tex]  

Explanation:

From  the question we are told that

   The  volume of trimethylamine, (CH3)3N(aq) is [tex]V_{t} = 20.00mL[/tex]

    The concentration of trimethylamine is [tex]C_t = 0.1000 \ M[/tex]  

    The  volume of HClO4(aq) is [tex]V_{h} = 9.48 mL[/tex]

    The  concentration of  HClO4(aq) is  [tex]C_h = 0.200 M[/tex]

      The Kb  value is  [tex]K_b = 6.5 * 10^{-5}[/tex]

Generally the the pOH of this reaction is mathematically represented as

       [tex]pOH = pK_b + log [\frac{N_h}{N_b} ][/tex]

Here [tex]N_h[/tex] is the number of moles of acid which is evaluated as

      [tex]N_h = C_h * V_h[/tex]

=>    [tex]N_h = 0.200 * 9.48[/tex]

=>    [tex]N_h = 1.896[/tex]

Here [tex]N_t[/tex] is the number of moles of acid which is evaluated as

      [tex]N_t = C_t * V_t[/tex]

=>    [tex]N_t = 0.100 * 20[/tex]

=>    [tex]N_t = 2[/tex]

So

     [tex]pOH = -log(K_b) + log [\frac{N_h}{N_b} ][/tex]

     [tex]pOH = -log(6.5*10^{-5}) + log [\frac{1.896}{2} ][/tex]

=>   [tex]pOH = 4.1639[/tex]

Generally the pH is mathematically represented as

       [tex]pH = 14 - pOH[/tex]

=>    [tex]pH = 14 - 4.1639[/tex]  

=>    [tex]pH = 9.84[/tex]  

Answer: C

Explanation: Everything else is true.

Its called "Ammonium thiocyanate" Have a great day!! <3

Answer:

it is called Ammonium Thiocyanate or Thiourea

Explanation:

it is made made up of 2 nitrogen atoms, 4 hydrogen atoms, 1 sulfur atom and 1 carbon atom. stay safe and have a great day! TPWK

Answer:

Explanation:  check my paage

Answer:

residue is whatever remains after something else has been removed while filtrate is the liquid or solution that has passed through a filter, and which has been separated from the filtride.

filtration id done by placing a filter paper on the beaker or container then pour the filtride then let it settle and it will pass through and you will have the fitrate and residue

Explanation:

Answer:

5 valence elctrons

Explanation:

the outer most orbitals, 3s2 and 3p3 contains 5 electrons, thus valences electrons for P is 5

Answer:

3 blue beads

1 red beads

4 green beads

Explanation:

The compound given:

               Ca₃PO₄

Elements in the compound are:

Ca

P

O

  Number of atoms are :

Ca - 3

P - 1

O  - 4

blue beads to model Calcium

red beads to model Phosphorus

green beads to model Oxygen

    3 blue beads

    1 red beads

   4 green beads

Answer: 10

Explanation:

4Al + 2O2 --> 2Al2O3

This is the balanced equation so there are 2*2 +2*3 = 4+6 =10

Answer:

work out if it's either going to sink or float

Explanation:

this can be carried out by calculating the numbers

Answer:

52.8 g of O2.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

4Al + 3O2 —> 2Al2O3

From the balanced equation above,

4 moles of Al reacted with 3 moles of O2 to produce 2 moles of Al2O3

Next, we shall determine the number of mole of O2 needed to react with 2.2 moles of Al. This can be obtained as follow:

From the balanced equation above,

4 moles of Al reacted with 3 moles of O2.

Therefore, 2.2 moles of Al will react with = (2.2 × 3)/4 = 1.65 moles of O2.

Thus, 1.65 moles of O2 is needed for the reaction.

Finally, we shall determine the mass of O2 needed as shown below:

Mole of O2 = 1.65 moles

Molar mass of O2 = 2 × 16= 32 g/mol

Mass of O2 =?

Mole = mass/Molar mass

1.65 = mass of O2 /32

Cross multiply

Mass of O2 = 1.65 × 32

Mass of O2 = 52.8 g

Therefore, 52.8 g of O2 is needed for the reaction.

Answer:

The answer is

Explanation:

The number of molecules present can be found by using the formula

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

N = 4.21 × 6.02 × 10²³

We have the final answer as

Hope this helps you

Answer:

adding a catalyst will increase the reaction rate.

Explanation:

im like 95% sure thats right.

Answer:

A. C. D

Explanation:

ap ex

actual yield = 0.182 mole

theoretical yield : 0.484 mole

percentage mole(% yield)=37.6%

Percent yield is the comparison of the amount of product obtained from a reaction with the amount you calculated

General formula:

Percent yield = (Actual yield / theoretical yield )x 100%

An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients

Reaction

Fe₂O₃+3C⟶2Fe+3CO

a. actual yield of Fe mole

10.2 g produced

[tex]\tt mol~Fe=\dfrac{10.2}{56}=0.182[/tex]

b. percentage mole and theoretical yield

0.242 mol Fe₂O₃ = 2 x 0.242 mol Fe = 0.484 mol (theoretical yield)

percentage yieldpercentage mole)

[tex]\tt \dfrac{0.182}{0.484}=0.376=37.6\%[/tex]

Answer:

ABC

Explanation:

hrdjyt

Answer:

32.5

Explanation:

2C⁴H¹⁰ needs 13 O²

5 C⁴H¹⁰ needs (13/2 × 5) O² = 32.5 O²

The answer is D, 32.5

(I took the test)

Answer:

0.343

Explanation:

Step 1: Given data

Step 2: Calculate the partial pressure of Kr

The total pressure of the mixture is equal to the sum of the partial pressures of the individual gases.

P = pXe + pAr + pKr

pKr = P - pXe - pAr

pKr = 6.70 atm - 1.60 atm - 2.80 atm

pKr = 2.30 atm

Step 3: Calculate the mole fraction of Kr

We will use the following expression.

X(Kr) = pKr/P

X(Kr) = 2.30 atm/6.70 atm

X(Kr) = 0.343

Considering the Dalton's partial pressure, the mole fraction of Kr is 0.34.

The pressure exerted by a particular gas in a mixture is known as its partial pressure.

So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{1} +P_{2} +...+P_{n}[/tex] where n is the number of gases.

This relationship is due to the assumption that there are no attractive forces between the gases.

Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture.

So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:

[tex]P_{A} =x_{A} P_{T}[/tex]

In this case, you know:

So, replacing in the Dalton's partial pressure law:

[tex]P_{T} =P_{Xe} +P_{Ar} +P_{Kr}[/tex]

6.70 atm= 1.60 atm + 2.80 atm + [tex]P_{Kr}[/tex]

6.70 atm- 1.60 atm- 2.80 atm= [tex]P_{Kr}[/tex]

2.30 atm=[tex]P_{Kr}[/tex]

Then: [tex]P_{Kr} =x_{Kr} P_{T}[/tex]

2.30 atm= [tex]x_{Kr}[/tex] 6.70 atm

[tex]x_{Kr}[/tex] =2.30 atm ÷6.70 atm

[tex]x_{Kr}[/tex] = 0.34  

In summary, the mole fraction of Kr is 0.34.

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Answer:

Physical

Explanation:

No new substance is formed.

The process can be reversed using evaporation to separate the sugar from the water

So the change is physical

Hope this helps :)

Answer:D

Explanation:I did it on study island.

Radio waves are not used to generate medical images because as per the electromagnetic spectrum ,the radio waves  carry little energy that they pass through most atoms without interaction.

The electromagnetic spectrum consists of  radiation  which consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.

The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.

In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.

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#SPJ2

Answer:

compound is sp3.

Explanation:

Answer:

The strong forces oppose the electromagnetic force of repulsion between protons. Like ”glue” the strong force keeps the protons together to form the nucleus. The strong forces and electromagnetic forces both hold the atom together.

Explanation:

Hope This helps

Answer:

The strong forces oppose the electromagnetic force of repulsion between protons.

Answer:

From the numerical steps highlighted under explanation, the average atomic mass of bromine is 79.91 u

Explanation:

The steps to be taken will involve;

1) Find the number of isotopes of bromine.

2) Identify the atomic mass and relative abundance of each of the isotopes.

3) Multiply the atomic mass of each of the isotopes by their corresponding values relative abundance value.

4) Add the value in step 3 above to get the average atomic mass of bromine.

Now;

Bromine has 2 isotopes namely;

Isotope 1: Atomic mass = 78.92amu and a relative abundance of 50.69%.

Isotope 2: Atomic mass = 80.92amu and a relative abundance of 49.31%.

Using step 3 above, we have;

(78.92 × 50.69%)

And (80.92 × 49.31%)

Using step 4 above, we have;

(78.92 × 50.69%) + (80.92 × 49.31%) ≈ 79.91 u

The atomic mass of bromine has been calculated as 79.9062 amu.

The relative atomic mass of the element has been given as the mass of each isotope with respect to their abundance.

The atomic mass has been given as:

[tex]amu=\sum mass\;\times\;\% Abundance[/tex]

The available isotopes of Bromine have been:

Isotope 1 = 78.92 amu, and 0.5069 % abundance

Isotope 2= 80.92 amu, and 0.4931 % abundance

Submitting the values for the atomic mass unit of bromine ([tex]amu_{\text{Br}}[/tex]):

[tex]amu_{\text {Br}}= (78.92\;\times\;0.5069)\;+\;(80.92\;\times\;0.4931)\\amu_{\text{Br}}=40.0045\;+\;39.9016\\amu_{\text{Br}}=79.9062[/tex]

The atomic mass of bromine has been calculated as 79.9062 amu.

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Explanation:

The IUPAC system of nomenclature aims to ensure

that every organic compound has a unique, unambiguous name.that the IUPAC name of any compound conveys the structure of that compound to a person familiar with the system.

One way of checking whether the name you have given to an alkane is reasonable is to count the number of carbon atoms implied by the chosen name. For example, if you named a compound 3‑ethyl-4‑methylheptane, you have indicated that the compound contains a total of 10 carbon atoms—seven carbon atoms in the main chain, two carbon atoms in an ethyl group, and one carbon atom in a methyl group. If you were to check the given structure and find 11 carbon atoms, you would know that you had made a mistake. Perhaps the name you should have written was 3‑ethyl-4,4‑dimethylheptane!

Answer: d

Explanation:

On edg

Answer:

carbon-13

Explanation:

Answer:

ether group

Explanation: I looked it up