A laser emits light at a wavelength of 678 nm. How many photons are required to emit 1 joule of energy?

Answer:

6 moles

Explanation:

From the equation you can see that twice as many HCL moles are used as H2 produced

2 x 3 = 6 moles  of HCL required

Empirical formula of the Cyclopropane = C[tex]H_{2}[/tex]

Molecular formula  of the Cyclopropane = [tex]C_{3} H_{6}[/tex]

Cyclopropane is a cyclic compound having 3 carbon atoms in a ring.

As we know carbon is having 4 valency, that means it can form 4 bonds with other atoms.

In case of cyclopropane each carbon atom is attached with 2 carbon atoms in a ring, so 2 valency of each carbon atom is used in a ring formation.

The remaining 2 valency are satisfied by hydrogen atoms.

Here, 3 carbons are there so 6 hydrogens are used to satisfy their valency.

An empirical formula is a simple representation of ratio of the atoms present, while a molecular formula is a detailed representation of the total number of atom.

So here, carbon and hydrogen ratio is 1:2 , from this the Empirical formula of the Cyclopropane became C[tex]H_{2}[/tex]

And the molecular formula of  the Cyclopropane is [tex]C_{3} H_{6}[/tex].

Learn more about molecular formula here...

https://brainly.com/question/15092254

#SPJ10

Answer:

D

Explanation:

we use noble gas configuration of Kr because Kr atomic number is nearest to Sr

the atomic number of Kr and Sr

is equal to 36 and 38 based on this we write the electron configuration

1s2 ,2s2 , 2p6 , 3s2 , 3p6 , 4s2 , 3d10 , 4p6 === Kr and 5s2

Answer: D.

Explanation:

[Kr]5s2

Answer:

The bonds between atoms in the reactants are rearranged to form new compounds in chemical reactions, but none of the atoms disappear and no new ones are formed. As a consequence, chemical equations must be balanced, meaning that the number and kinds of atoms must be the same on both sides of the reaction arrow.

Explanation:

Explanation:

because of to obey the law of conservation mass

you know the law of conservation mass states that matter is neither created nor destroyed during chemical reaction means the mass of reactants is equal to the mass of product

Answer:

2HBr + Ba(OH)2 ____ BaBr2 + 2H2O

The numbers placed in front of formulas to balance equations

Answer:

if the Florida inters into the land se hokar gar ke bill Tak jane ke process Florida kahte hai aur bur ka bal se doodh chusne Tak wo Florida s

Humidity, thermometer, and rainfall factors affect the shape of Florida, making the shape different.

In general, a molecule's electron pairs will take on a structure that maximizes theirs from one another.

Even charges repel one another, whereas dissimilar charges attract H₂O, for instance, containing two pairs of lone electrons but taking on an angular form.

Sand ridges, like the Lake Wales Ridge, were created during dry times from sediments that had been transported by ocean currents and deposited to form islands.

Latitude, land and water distribution, dominant winds, hurricanes, pressure systems, and ocean currents are the main variables that influence Florida's climate.

Therefore, as glaciers retreated throughout cooling cycles, sea levels dropped and Florida occasionally doubled in size.

Learn more about Florida, here:

https://brainly.com/question/12732190

#SPJ2

The complete table is inserted.

A table is given,

Formulas used:

pH=  -log(H⁺)

pOH=  -log(OH⁻)

pH+ pOH=14

Calculations:

For A: (H⁺)=2×10⁻⁸M

Using the pH formula:

pH=  -log(H⁺)=-log(2×10⁻⁸)=7.69

pOH=14 - 7.69=6.3

Calculating OH concentration,

pOH=  -log(OH⁻)

6.3= -log(OH⁻)

(OH⁻)=5.011×10⁻⁷M

Hence, the nature of A is basic.

Similarily,

For B,

(OH⁻)=1×10⁻⁷

Using the pH formula:

pOH=  -log(OH⁻)= -log(1×10⁻⁷)=7

pH=14-7=7

Calculating H concentration,

pH=  -log(H⁺)

7= -log(H⁺)

(H⁺)=1×10⁻⁷M

Hence, the nature of B is neutral.

Similarily,

For C,

pH=12.3

Using the pH formula:

pOH=14-12.3=1.7

Calculating H concentration,

pH=  -log(H⁺)

12.3= -log(H⁺)

(H⁺)=5.011×10⁻¹³M

Calculating OH concentration,

pOH=  -log(OH⁻)

1.7= -log(OH⁻)

(OH⁻)=1.99×10⁻²M

Hence, the nature of C is Basic.

Similarily,

For D,

pOH=6.8

Using the pH formula:

pH=14-6.8=7.2

Calculating H concentration,

pH=  -log(H⁺)

7.2= -log(H⁺)

(H⁺)=6.309×10⁻⁸M

Calculating OH concentration,

pOH=  -log(OH⁻)

6.8= -log(OH⁻)

(OH⁻)=1.58×10⁻⁷M

Hence, the nature of D is basic.

Learn more about the acid and bases here:

https://brainly.com/question/16189013

#SPJ10

The northern slope will have the least precipitation if winds blow against a mountain from the south.

This is referred to as the degree of steepness on a surface such as rocky areas etc.

When wind blows on the southern part of a mountains, it gets stuck which is why the northern slope have the least precipitation.

Read more about Slope here https://brainly.com/question/24208141

#SPJ1

#CarryOnLearning

b

Explanation:

containing of ion electron and protons

The hazard symbol that pesticides have are skull and cross bones.

Hazard symbols represent those symbols that are used as a warning sign towards materials that are dangerous to health.

Example of symbols used are:

Therefore, the hazard symbol that pesticides have are skull and cross bones.

Learn more about pesticides here:

https://brainly.com/question/6589507

#SPJ1

The hazard symbol of pesticides is a picture of the skull and crossbones.

Pesticides are known as  substances that are meant to control or destroy pests. They include herbicide, insecticide, nematicide, avicide, rodenticide, bactericide, insect repellent, etc.

The hazard symbol of pesticides is a picture of the skull and crossbones

Thus, the hazard symbol of pesticides is a picture of the skull and crossbones.

Read more about pesticides here:

https://brainly.com/question/6662547

#SPJ1

3.8mL of 0.42 phosphoric acid is required.

Reaction

2H3PO4 + 3CaCL3 → Ca3(PO)4 + 6HCl

moles CaCl2 =0.16 mol/L x0.010 L = 0.0016 mol

moles of H3Po4

= 0.0016mol of CaCl2 x 2 mole of H3PO4/3mole of CaCl2

= 0.00106 mol

V of H3PO4 = 0.0016/0.42 = 0.0038L = 3.8mL

V of H3PO4=3.8mL

To know more about calculation in milliliters refer to:-

https://brainly.com/question/23276655

#SPJ10

Activation energy is required so reactants can move together, overcome forces of repulsion, and start breaking bonds.

The minimum amount of energy that is needed to activate atoms or molecules to a condition in which they can undergo a chemical transformation or physical transport.

The activation energy of this chemical reaction is high that it will not start at room temperature. This is why a source of heat is required to start the fire: the “energy barrier” must be overcome before the reaction can proceed further.

In any chemical reaction, existing chemical bonds should be broken before new bonds formation. The breaking of chemical bonds requires an input of energy. In some reactions, the thermal energy at room temperature is enough to break the bonds.

In other cases, the thermal energy at room temperature does NOT give enough energy to break the needed bonds (by facilitating sufficiently energetic molecular collisions) to get the reaction started.

Learn more about activation energy here:

https://brainly.com/question/11334504

#SPJ1

The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve. Hence, option A is correct.

Weak acids are acids that don't completely dissociate in solution.

A weak acid is an acetic acid. It has a of 1.8⋅[tex]10^{-5}[/tex]. Calculate how much it will dissociate in water. Since acetic acid is a weak acid so large part will not dissociate completely.

[tex]k_a=\frac{[CH_3COO^-]H^+]}{[CH_3COOH]}[/tex]

B is not true, it shows the titration curve for weak/strong acid titrated with a strong base. When choosing an indicator for colourimetric titration select one so that the pH jump at the equivalence point contains the interval p±1. Phenolphthalein has a p≈9, so to decide if it is a suitable indicator check if the pH jumps from 8 to 10 at the equivalence point.

C is not true either because of the very slow reaction.

Learn more about weak acid here:

https://brainly.com/question/12811944

#SPJ1

Electrons in the Bohr model follow the number of elements in the rows of the periodic table.

2 in the first orbit

8 in the second and third ring

18 in the fourth etc...

The Bohr model is a simplistic means of explaining the placement of the subatomic particles of the elements of the periodic table.

The Bohr model arrangement of electrons follows the same pattern as the periodic table.

2 elements in the first row, and 2 electrons in the first orbit.

8 elements in the second row, and 8 electrons in the second orbit.

8 elements in the third row, and 8 electrons in the third orbit.

The fourth and fifth orbits would therefore hold 18 electrons.

For most chemists, the Bohr model does not work well beyond the third row of the periodic table because the model becomes quite oversized and bulky.

Answer:

Tablets are made from salts of iron hence it does not look like iron.

Explanation:

The balanced redox equations of the reactions are:

Balanced redox equations are those in which the atoms and electrons transferred are equal on both sides of the equation.

The balanced redox equations of the reactions are given below:

(3a) Balanced REDUCTION half reaction of the equation under basic conditions:

(3b)Balanced OXIDATION half reaction of the equation under basic conditions:

(4a) Balanced REDUCTION half reaction of the equation under acidic conditions:

(4b) Balanced OXIDATION half reaction of the equation under acidic conditions:

Therefore, the balanced oxidation and reduction half reactions are balanced by adding the numerical coefficients to the reacting species as well hydrogen ions, hydroxide ions, water molecules and electrons to the appropriate side of the reactions.

Learn more about redox equations at: https://brainly.com/question/1161855

#SPJ1

Answer:

The answer is "B will give up two electrons to form bonds".

Explanation:

To first solve this multiple choice question, we need to identify the Atoms, A and B.

We can do this by looking at their amount of electrons.

For instance,

A = Neon = 10 Electrons

B = Magnesium = 12 Electrons

With this information we can then look at both elements charges to see what they need to form a bond.

In this case Neon doesn't want to form a bond, since they're in a complete octet, however Magnesium does not have a complete octet. So, it wants to give up two electrons to form a bond (2+ charge shows us that).

This then shows us that Option 2, "B will give up two electrons to form bonds" is correct.

Answer:

B will give up two electrons to form bonds

Explanation:

Answer:

can you post a photo? to help y with the question

Explanation:

The number of moles of gas, a balloon inflated to 7 L of volume at STP will be 0.31 moles.

The molar volume of a gas is the volume of one mole of a gas at STP.

At STP, one mole (6.02×10²³ particles) of any gas occupies a volume of 22.4 L

Therefore,

If 1 mole of any gas occupies 22.4 L of volume at STP

Then, X mole of gas occupies 7 L of Volume at STP

Now,

Let's equate both the above conditions ;

X / 7 L = 1 / 22.4 L

  X      = 1/ 22.4 L x 7 L  

  X      = 0.31 moles

Hence, the number of moles of gas, a balloon inflated to 7 L of volume at STP will be 0.31 moles.

Learn more about Molar volume here ;

https://brainly.com/question/4172228

#SPJ1

Copper-plating is a chemical change in which copper ions become neutral copper atoms by accepting electrons which then are deposited on the material to be coated.

copper-plating?Copper-plating is the process by which a layer of copper is used to coat another material using the process of electrolysis.

At the molecular level, copper ions in solution accept electrons to become neutral copper atoms which then are deposited on the material, thereby coating.

This is an example of a chemical change since it us not easily reversible and new products are formed.

Learn more about copper-plating at: https://brainly.com/question/14048494

#SPJ1

The ⁴⁰₁₈X is the symbol for ⁴⁰₁₈Ar - atom and it has 18 protons, 18 electrons, and 22 neutrons.

Mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom.

In the given element,  ⁴⁰₁₈X,  Subscript 18 is the number of proton and is also equal to the number of electron. While supercript 40 is the atomic mass.

The number of neutrons is given by subtracting the proton number from the mass number.

Therefore,

Number of Neutron = Mass Number - Atomic Number

                                 = 40 - 18

                                 = 22 Neutrons

Learn more about Mass number here ;

https://brainly.com/question/18803094

#SPJ1

Answer:

95.45 moles

Explanation:

CO2 has mole weight  12 + 2 *16 = 44 gm/mole

4200 gm / 44 gm/mole = 95.45 moles

1.05 moles of oxygen gas are consumed in the reaction when 2.10 mol of magnesium burns.

A mole is defined as [tex]6.02214076 × 10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

We are given:

Moles of magnesium = 2.10 mol

For the given chemical reaction:

2Mg + O₂ → 2MgO.

By Stoichiometry of the reaction:

2 moles of magnesium react with 1 mole of oxygen gas.

So, 2.10 moles of magnesium will react with = [tex]\frac{1}{2}[/tex] X2.10 =1.05 moles

Hence, 1.05 moles of oxygen gas are consumed in the reaction.

Learn more about moles here:

https://brainly.com/question/8455949

#SPJ1

Taking into account definition of percent yield, the percent yield for the reaction is 91.17%.

In first place, the balanced reaction is:

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The following rule of three can be applied: if by reaction stoichiometry 159.7 grams of Fe₂O₃ form 111.7 grams of Fe, 50.5 grams of Fe₂O₃ form how much mass of Fe?

[tex]mass of Fe=\frac{50.5 grams of Fe_{2} O_{3} x111.7 grams of Fe}{159.7 grams of Fe_{2} O_{3}}[/tex]

mass of Fe= 35.32 grams

Then, 35.32 grams of Fe can be produced from 50.5 g iron(III) oxide.

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

[tex]percent yield=\frac{actual yield}{theorical yield}x100[/tex]

where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.

In this case, you know:

Replacing in the definition of percent yields:

[tex]percent yield=\frac{32.2grams}{35.32grams}x100[/tex]

Solving:

percent yield= 91.17%

Finally, the percent yield for the reaction is 91.17%.

Learn more about

the reaction stoichiometry:

brainly.com/question/24741074

brainly.com/question/24653699

percent yield:

brainly.com/question/14408642

#SPJ1

Answer:

CO2

Explanation:

100% CORRECT ON EDGE

The mass of water produced when 1.000 × 10³ g of LiOH is combined with 8.80 × 10² g CO₂  is 3.25 × 10² g H₂O.

Mass is defined as a dimensionless number used to describe the mass of a particle or item. The kilogram is the International System's (SI) preferred unit of mass (kg). Atoms make up everyday matter. A majority of an atom's mass is contained in its nucleus.

It is a neutralization process when lithium hydroxide and carbon dioxide combine to form water and lithium carbonate.

The reaction is [tex]\rm CO_2 + 2LiOH \rightarrow Li_2CO_3 + H_2O[/tex]

Neutralization reaction is defined as an acid and base reaction that produces an ionic molecule and potentially water.

Thus, the mass of water produced when 1.000 × 10³ g of LiOH is combined with 8.80 × 10² g CO₂  is 3.25 × 10² g H₂O.

To learn more about mass, refer to the link below:

https://brainly.com/question/19694949

#SPJ2

Answer: B

Explanation:

The weight of CoCl₂ used to make 0.5 ltr 1 Molar solution is 49.5g.

The weight of a substance can be calculated by multiplying the number of moles of the substance by its molar mass.

However,

the number of moles of CoCl₂ must be calculated using the following formula:

no of moles = 0.5L × 1M

no of moles = 0.5moles

Molar mass of CoCl₂ = 99g/mol

mass of CoCl₂  = 0.5 × 99

mass of CoCl₂  = 49.5g

Hence, the weight of CoCl₂ used to make 0.5 ltr 1 Molar solution is 49.5g.

Learn more about Mass here ;

brainly.com/question/26416088

#SPJ1

The number of moles of the gas at 77°C and 1.33 atm occupies a volume of 50.3 L is 2.35 moles. It can found with the help of Ideal gas equation.

The ideal gas equation is formulated as : PV = nRT.

In this equation, P refers to the pressure of the ideal gas, V is the volume of the ideal gas, n is the total amount of ideal gas that is measured in terms of moles, R is the universal gas constant, and T is the temperature.

Given ;

We know ;

Formula used ;

n = PV / RT

n = 1.33 x 50.3 / 0.081 x 350k

  =  2.35 moles.

Hence, The number of moles of the gas at 77°C and 1.33 atm occupies a volume of 50.3 L is 2.35 moles

Learn more about Ideal Gas here ;

https://brainly.com/question/27922399

#SPJ1

Answer:

Both metals and non-metals when burnt in oxygen form their oxides. Oxides of metals are basic in nature and oxides of non-metals are acidic in nature.