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Answer:

The major innovation made from Abacus to the present fifth generation​ is explained below in details.

Explanation:

Industrial Age - 1600

John Napier, a Scottish noble and diplomat consecrated much of his holiday time to the learning of mathematics. He was particularly engrossed in devising methods to aid estimates. His most famous offering was the discovery of logarithms. He listed logarithmic measures on a set of 10 board rods and thus was capable to do multiplication and division by equaling up numbers on the poles. These became recognized as Napier’s Bones.

Answer:

it's used to measure intensity of radioactivity in a sample of material

Answer:

62.03 g/mol

Explanation:

Answer:

oxygen is a reactant.

Explanation:

Combustion is the reaction with atmospheric oxygen forming carbon dioxide and water. Therefore, the essential condition is option B oxygen as a reactant.

Combustion is a type of reaction in which a molecule or compound reacts with atmospheric oxygen producing carbon dioxide and water. Combustion reaction is exothermic thus, evolves heat during reaction.

The general chemical equation for a combustion reaction can be written as:

[tex]\rm M + nO_{2} \rightarrow xH_{2}O + y CO_{2}[/tex]

Where, M be a reactant.

Combustion is an aerobic process that is only taking place in presence of oxygen. Hydrocarbon gases easily undergo combustion forming heat energy and they are used as fuels propellants.

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Hi

i hope this helps

Answer:

The Greek atom theory

Explanation:

The concept of the Greek atomos theory is an indivisible particle of matter, goes back to ancient Greece and a man named Democritus held that all matter could be subdivided only until some finite particle was reached.

Answer: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.

Answer:

797 mm hg = 1.04868 atm

Explanation:

1 atm = 760 mm hg

797 mm hg to atm is 1.0468 atm

Pressure is defined as the physical force exerted on an object. The force applied is perpendicular to the surface of objects per unit area.

There are many different types of units and prefixes that may be used in general practice to reflect pressure. Thus, it is ensured that all the measurements and their respective units are in the same framework when conducting pressure calculations.

Pascal is the SI unit of pressure, and is the basic pressure unit in the SI (the International System of Units) system.

Given,

Pressure = 797 atm

1 mm Hg = 0.00131579 atm

797 mm Hg = 0.00131579 × 797

= 1.04868 atm

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Answer:

12.3 L

Explanation:

Now we have that the rate of diffusion of the saturated hydrocarbon is R1

Rate of diffusion of sulphur dioxide is R2

Molar mass of hydrocarbon is M1

Molar mass of sulphur dioxide is 64 gmol-1

From Graham's law;

R1/R2 = √64/M1

2/1 =√64/M1

(2/1)^2 = (√64/M1)^2

4/1 = 64/M1

4M1 =64

M1 = 16

To obtain the number of moles of the gas;

(n*12) + (2n + 2) 1 = 16

12n + 2n + 2 = 16

14n + 2 = 16

14n = 16 - 2

n = 14/14

n = 1

Hence the hydrocarbon is CH4

Volume occupied by CH4 at STP = 22.4 L

Hence;

P1 = 1 atm

T1 = 273 K

V1 = 22.4 L

T2 = 300 K

P2 = 2 atm

V2 = ?

P1V1/T1 = P2V2/T2

P1V1T2 = P2V2T1

V2 = P1V1T2/P2T1

V2 = 1 * 22.4 * 300/2 * 273

V2 = 12.3 L

The volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Let the hydrocarbon be initially at standard temperature and pressure (STP)

Thus, we can obtain the new volume of the hydrocarbon by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(1 × 22.4) / 273 = (2 × V₂) / 300

22.4 / 273 = (2 × V₂) / 300

Cross multiply

273 × 2 × V₂ = 22.4 × 300

546 × V₂ = 6720

Divide both side by 546

V₂ = 6720 / 546

V₂ = 12.31 L

Thus, the volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

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Answer:

A

Explanation:

I took a test like this and my teacher said this was right so ye. hopefully I remembered correctly if its wrong im sorry ;C

Answer: A

Explanation: A thunderstorm forms when warm, moist air rises into cold air. Hope this helps. :)

Answer:

High amount of energy is required to dissociate these bonds and hence water molecules have a higher boiling point than expected.

Explanation:

Answer: The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods

The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Ideal gas is a hypothetical gas. Vanderwaal gas can behave as ideal gas at low pressure and high temperature. Therefore the final pressure is 1,750 mmHg.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of gas

V= volume of gas

n =number of moles of gas

T =temperature of gas

R = Gas constant = 0.0821 L.atm/K.mol

At constant volume, the above equation can be rearranged as

P₁/T₁ = P₂/T₂

Substituting all the given values in the above equation, we get

1500 ÷300= P₂÷350

P₂ =1,750 mmHg

Therefore the final pressure is 1,750 mmHg.

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Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

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

[tex]n = \frac{4 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 6.644518...[/tex]

We have the final answer as

Hope this helps you

Answer:

A

Explanation:

common sense

Answer:

are you good at sailing A.

The spontaneous reactions are said to be exothermic in nature. Hence, option B is correct.

The type of reaction that has not been utilizing energy input output to the reaction system in order to favor the formation of product are termed as exothermic reaction.

The entropy has been the tendency of the randomness of atoms in the system, and the enthalpy has been the energy of the system.

With the spontaneous reaction, there has been an increase in the entropy of the system with the formation of the products, and a decrease in the enthalpy. The reaction forms no use of the input energy, and thereby cannot be endothermic in nature.

Therefore, the reaction that is exothermic tends to be spontaneous reactions. Hence, option B is correct.

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Answer:

Chemical, cause physical are changes affecting the form of a chemical substance, but not its chemical composition. This doesn't affect the substance but the composition.

Explanation:

The statement that describes a physical change is a sculptor casts a statue in molten bronze and allows it to harden. The correct option is C.

"A physical change is one that simply affects the physical nature of the substance." Usually, increasing the temperature or applying pressure, both, will cause a physical change. In other words, physical changes are reversible.

All the other options like rusting of iron bolts on a bridge is a chemical change when iron reacts with oxygen in the air, it gets rust.

Similarly, silver cups exposed to air react with air is a chemical change, and option d, silver off magnesium that creates light, is also a chemical change.

Thus, the correct option is C. A sculptor casts a statue in molten bronze and allows it to harden.

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Answer:

1. 9.45 g

2. 66.9%

Explanation:

The balanced equation for the reaction is given below:

Cu(s) + 4HNO3(aq) —> Cu(NO3)2(aq) + 2NO2(g) + 2 H2O(l)

Next, we shall determine the mass of Cu that reacted and the mass of Cu(NO3)2 produced from the balanced equation. This can be obtained as follow:

Molar mass of Cu = 63.5 g/mol

Mass of Cu from the balanced equation

= 1 × 63.5 = 63.5 g

Molar mass of Cu(NO3)2 = 63.5 + 2[14 + (3×16)]

= 63.5 + 2[14 + 48]

= 63.5 + 2[62]

= 63.5 + 124

= 187.5 g/mol

Mass of Cu(NO3)2 from the balanced equation = 1 × 187.5 = 187.5 g

Summary:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

1. Determination of the theoretical yield of Cu(NO3)2. This can be obtained as follow:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

Therefore, 3.20 g of Cu will react to produce = (3.20 × 187.5) / 63.5 = 9.45 g of Cu(NO3)2.

Thus, the theoretical yield of Cu(NO3)2 is 9.45 g.

2. Determination of the percentage yield of Cu(NO3)2.

Actual yield of Cu(NO3)2 = 6.32 g

Theoretical yield of Cu(NO3)2 = 9.45 g.

Percentage of the Cu(NO3)2 =?

Percentage yield = Actual yield /Theoretical yield × 100

Percentage yield of Cu(NO3)2 = 6.32/9.45 × 100

Percentage yield of Cu(NO3)2 = 66.9%

The theoretical yield of Cu(NO₃)₂ is 9.445 g

The percent yield of Cu(NO₃)₂ is 66.91%

From the question.

We are to determine the theoretical yield of Cu(NO₃)₂,

First and foremost, we will write the balanced chemical equation for the reaction properly

The balanced chemical equation for the reaction is

Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

This means

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂, 2 moles of NO₂ and 2 moles of H₂O

To determine the theoretical yield of Cu(NO₃)₂,

First, we will determine the number of moles of Cu that reacted

Mass of Cu = 3.20 g

Molar mass of Cu = 63.546 g/mol

From the formula

[tex]Number\ of\ moles =\frac{Mass}{Molar\ mass}[/tex]

∴ Number of moles of Cu = [tex]\frac{3.20}{63.546}[/tex]

Number of moles of Cu present = 0.050357 moles

The number of moles of Cu that reacted is 0.050357 moles

Since,

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂

Then,

0.050357 moles of Cu will react with 0.201428 moles of HNO₃ to produce 0.050357 moles of Cu(NO₃)₂

∴ 0.050357 moles of Cu(NO₃)₂ will be produced during reaction

Now, for the theoretical yield of Cu(NO₃)₂  

From the formula

Mass = Number of moles ×  Molar mass

Molar mass of Cu(NO₃)₂ = 187.56 g/mol

∴ Theoretical yield of Cu(NO₃)₂ = 0.050357 × 187.56

Theoretical yield of Cu(NO₃)₂ = 9.445 g

Hence, the theoretical yield of Cu(NO₃)₂ is 9.445 g

For the percent yield of Cu(NO₃)₂

[tex]Percent \ yield = \frac{Actual \ yield}{Theoretical \ yield } \times 100 \%[/tex]

From the question

Actual yield = 6.32 g

But,

Theoretical yield = 9.445 g

∴ Percent yield of Cu(NO₃)₂ = [tex]\frac{6.32}{9.445} \times 100\%[/tex]

Percent yield of Cu(NO₃)₂ = [tex]\frac{632}{9.445}\%[/tex]

Percent yield of Cu(NO₃)₂ = 66.91%

Hence, the percent yield of Cu(NO₃)₂ is 66.91%

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Answer:

law of conservation of mass

Explanation:

According to the law of conservation of mass, mass is neither created nor destroyed.

This is actually the law that guides the balancing of chemical reaction equations.

On the left side we have four atoms of hydrogen and two atoms of oxygen. Exactly the same number of atoms of each element is seen on the right hand side in accordance with the law of conservation of mass.

Answer: The distance is slightly less than 3.5 m

Explanation: assuming wall and target are the same thing, and the bullet has constant velocity, the bullet will travel 7 m in half a second, so half that distance is 3.5 m.

In reality, the bullet is decelerating (at an unknown rate) so the distance is slightly less than 3.5 m.

There is also a vertical velocity component, which means it hits the target/wall at an angle. The trajectory is such that it hits the wall above the shooter because the ricochet hits at ~the level at which it left the firearm.

If the wall was absent, the bullet would have described a parabola which brough it back to the initial level after 7m. This could be calculated, but it means that the actual distance between the shooter and the wall is slightly less than 3.5 m

In addition, the collision with the wall is not 100% elastic, so the velocity aftercthe ricochetvis further reduced.

A calculation would be complex because these confounding factors are not completely independent of each other,  but all reduce the average velocity and therefore the distance.

Therefore it is only possible to say that the distance was somewhat less than 3.5 m

Answer:

1. 0.28M

2. 24mL

3. 0.002295moles of NaOH.

Explanation:

1. The 6.0M HCl solution is diluted from 35mL to 750mL, that is:

750mL / 35mL = 21.43 times

The 6.0M HCl solution is diluted 21.43 times, the final concentration is:

6.0M / 21.43 = 0.28M

2. First, we need to convert grams of CuNO3 to moles and then, as molarity is moles per liter we can solve for volume of solution in liters and convert it to mililiters:

Moles CuNO3 -Molar mass 124.9g/mol:

2.49g * (1mol / 124.9g) = 0.020 moles of CuNO3

Volume is:

0.020 moles * (1L / 0.830mol) = 0.0240L * (1000mL / 1L) = 24mL

3. In 13.5mL = 0.0135L of 0.17M NaOH the moles are:

0.0135L * (0.17mol / L) = 0.002295moles of NaOH

Answer:

Explanation:

The lewis structure (indicating all the atoms and patterns provided as hint in the question) of glycine can be seen in the attachment below. While the chemical structure of glycine can be seen below

         H

          |

H₂N - C - C =O

          |      \

         H      OH

The structure (of glycine) above provides a "fair idea" of how the lewis structure will be.

Answer: A. They are not reactive because their outer valence electron shell is full.

Explanation:

Noble gases are group 18 elements which are Helium , Neon , Argon , Krypton , Xenon and radon.

Noble gases have general electronic configuration of [tex]ns^2np^6[/tex]

As the sub-shells of noble gases is fully filled and their octet is complete. Hence, it will not gain or lose any electron and thus is non reactive in nature.

They do not react with other elements under ordinary conditions.

Thus the correct statement is they are not reactive because their outer valence electron shell is full.

Answer:

mercury

Explanation:

Answer:

C. potential energy

Explanation:

got 100 on edg

The atomic number of this atom : 8

Given

Atomic model (attached)

Required

The atomic number

Solution

To determine the atomic number of an element, we can look at the number of electrons or the number of protons, because

atomic number = number of protons = number of electrons in neutral atoms

While the mass number is the number of neutrons + the number of protons located in the atomic nucleus

The charge of each of these atomic sub particles:

If we look at this atomic model, there are 8 electrons in the shell, consisting of 2 electrons in the first shell and 6 electrons in the second shell (which can also be called valence electrons)

Whereas in the atomic nucleus there are 8 protons and 10 neutrons

Answer:8

Explanation:

Answer:

detail is given below.

Explanation:

Chemical equation:

AuBr₃ + Cl₂    →       AuCl₃ + Br₂

Balanced chemical equation:

2AuBr₃ + 3Cl₂    →       2AuCl₃ + 3Br₂

The reactants of this chemical reaction are,

AuBr₃

Cl₂

The product of this chemical reaction is,

AuCl₃

Br₂

Reaction type:

The reaction type is single replacement reaction.

Single replacement:

It is the reaction in which one elements replace the other element in compound.

AB + C → AC + B

In a similar way chlorine replace the bromine and form gold(III) chloride and bromine gas.