why compounds with weak molecular forces are usually gases.

Answer:

Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. Nowadays, generation includes both hardware and software, which together make up an entire computer system.

5 generation of computer  

Main electronic component: based on artificial intelligence, uses the Ultra Large-Scale Integration (ULSI) technology and parallel processing method.

ULSI – millions of transistors on a single microchip

Parallel processing method – use two or more microprocessors to run tasks simultaneously.

Language – understand natural language (human language).

Power – consume less power and generate less heat.

Speed – remarkable improvement of speed, accuracy and reliability (in comparison with the fourth generation computers).

Size – portable and small in size, and have a huge storage capacity.

Input / output device – keyboard, monitor, mouse, trackpad (or touchpad), touchscreen, pen, speech input (recognise voice / speech), light scanner, printer, etc.

Example – desktops, laptops, tablets, smartphones, etc.

3 generation of computer

Main electronic component – integrated circuits (ICs)

Memory – large magnetic core, magnetic tape / disk

Programming language – high level language (FORTRAN, BASIC, Pascal, COBOL, C, etc.)

Size – smaller, cheaper, and more efficient than second generation computers (they were called minicomputers).

Speed – improvement of speed and reliability (in comparison with the second generation computers).

Input / output devices – magnetic tape, keyboard, monitor, printer, etc.

Examples – IBM 360, IBM 370, PDP-11, UNIVAC 1108, etc.

4 generations of computer

Main electronic component – very large-scale integration (VLSI) and microprocessor.

VLSI– thousands of transistors on a single microchip.

Memory – semiconductor memory (such as RAM, ROM, etc.)

RAM (random-access memory) – a type of data storage (memory element) used in computers that temporary stores of programs and data (volatile: its contents are lost when the computer is turned off).

ROM (read-only memory) – a type of data storage used in computers that permanently stores data and programs (non-volatile: its contents are retained even when the computer is turned off).

Programming language – high level language (Python, C#, Java, JavaScript, Rust, Kotlin, etc.).

Explanation:

Following are the kinetic theory of gases postulates:

1) Space-volume to molecules ratio is negligible.

2)There is no force of attraction between the molecules at normal temperature and pressure. The force of attraction between the molecules build when the temperature decreases and the pressure increases.

3) There is large space between the molecules resulting in continuous motion.

4) The free movement of molecules results in collision which is perfectly elastic.

5) The molecules have kinetic energy due to random movement. But the average kinetic energy of these molecules differs with temperature.

6) Molecules exert pressure on the walls of the container.

Answer:

Molarity is a measure of concentration

I Hope its right if not so advance sorry :)

The molarity measures the number of moles of the solute present per liter of the solution and it measures the concentration of the solution. option D is correct.

Molarity is the amount or the number of moles present in per liter of the solution it is the unit to measure the concentration of the moles.

Unit of molarity will be moles per liter and the temperature does not affect the molarity of the solution. molarity can be calculated by dividing the concentration of the solution by the molar mass of the given element.

molarity = weight / mass ×  1000/ volume in liters.

With the help of this formula, we can calculate the molarity.

Therefore,  molarity measures the number of moles of the solute present per liter of the solution and it measures the concentration of the solution. option D is correct.

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Answer:

See explanation

Explanation:

A redox reaction equation shows a gain/loss of electrons from left to right in a reaction. In a redox reaction, a specie looses electrons while another specie gains electrons.

Considering the equation; 2Al(s) + 3Cu(NO3)2(aq) -----> 3Cu(s) + 2Al(NO3)3(aq)

The oxidation state of Al reactant is zero since the oxidation state of all uncombined elements is zero. The oxidation state of All in the product is +3

The oxidation state of the copper in the reactant is +2. The oxidation state of copper in the product is zero.

The oxidation state of N in the reactant and product is +5.

The oxidation state of oxygen in the reactant and product is (-2).

This is a redox reaction because from left to right, Al was oxidized (oxidation number increased from zero to +3) while Cu was reduced (oxidation number decreased from +2 to zero).

This question is incomplete, the complete question is;

Dimethyl ether, a useful organic solvent, is prepared in two steps.

In the first step, carbon dioxide and hydrogen react to form methanol and water:  

CO₂(g) + 3H₂(g)  →  CH₃OH(l) + H₂O(l)                ΔH₁ = -131.kJ

In the second step, methanol reacts to form dimethyl ether and water:

2CH₃OH(l)   →   CH₃OCH₃(g) + H₂O(l)                ΔH₂ = 8.kJ

Calculate the net change in enthalpy for the formation of one mole of dimethyl ether from carbon dioxide and hydrogen from these reactions. Round your answer to the nearest kJ.

Answer:

the net change in enthalpy for the formation of one mole of dimethyl ether is -254 kJ

Explanation:

Given the data in the question;

For the First Step;

CO₂(g) + 3H₂(g)  →  CH₃OH(l) + H₂O(l)                ΔH₁ = -131.kJ

For the First Step;

2CH₃OH(l)   →   CH₃OCH₃(g) + H₂O(l)                ΔH₂ = 8.kJ

Using Hess's Law of Constant Heat Summation;

" regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes "

we multiply step 1 reaction by the coefficient of 2

2CO₂(g) + 2×3H₂(g)  →  2CH₃OH(l) + 2H₂O(l)                ΔH₁ = 2 × -131.kJ

we have

2CO₂(g) + 6H₂(g)  →  2CH₃OH(l) + 2H₂O(l)                ΔH₁ = -262 kJ

2CH₃OH(l)   →   CH₃OCH₃(g) + H₂O(l)                       ΔH₂ = 8 kJ

{ 2CH₃OH cancels 2CH₃OH }

Hence, we have;

2CO₂ + 6H₂  →  CH₃OCH₃(g) + 3H₂O(l)

So According to Hess's Law;

ΔH[tex]_{sum[/tex] = ΔH₁ + ΔH₂

we substitute

ΔH[tex]_{sum[/tex] = -262 kJ + 8 kJ

ΔH[tex]_{sum[/tex] = -254 kJ

Therefore, the net change in enthalpy for the formation of one mole of dimethyl ether is -254 kJ

Answer:

Explanations you mom bumb it’s a:

It’s 2

Answer:

Average specific heat capacity of metal = 0.57 J/g°C

Explanation:

Heat lost = Heat gained

Heat energy gained or lost, H = mcΔT

where m = mass of substance, c = specific heat capacity, ΔT = temperature change

Trial 1:

Heat lost by metal = -[2.746 g × c × ΔT]

ΔT = (26.3 - 72.1) °C = -45.8 °C

Heat lost by metal = -[2.746 g × c × (-45.8 °C)] = c × (125.7688)g°C

Heat gained by water = 15.200 × 4.18 × ΔT

ΔT = (26.3 - 24.7) = 1.6 °C

Heat gained by water = 15.200 × 4.18 × 1.6 = 101.6576 J

From Heat lost = Heat gained

c × (125.7688)g°C = 101.6576 J

c = 101.6576 J / 125.7688 g°C

c = 0.8083 J/g°C

Trial 2:

Heat lost by metal = -[2.750 g × c × ΔT]

ΔT = (26.2 - 72.2)°C] = - 46 °C

Heat lost by metal = -[2.750 g × c × (-46 °C)

Heat lost by metal = c × (126.5) g°C

Heat gained by water = 15.206 × 4.18 × ΔT

ΔT = (26.2 - 24.6) = 1.6 °C

Heat gained by water = 15.206 × 4.18 × 1.6 = 101.697728 J

From Heat lost = Heat gained

c × (126.5)g°C = 101.6977 J

c = 101.697728 J / 126.5 g°C

c = 0.8039 J/g°C

Trial 3:

Heat lost by metal = -[2.900 g × c × ΔT]

ΔT = (24.7 - 71.9)°C] = - 47.2 °C

Heat lost by metal = -[2.900 g × c × (- 47.2 °C)

Heat lost by metal = -[2.900 g × c × (- 47.2)°C] = c × (136.88)g°C

Heat gained by water = 15.201 × 4.18 × ΔT

ΔT = (24.7 - 24.5) = 0.2 °C

Heat gained by water = 15.201 × 4.18 × 0.2 = 12.708036 J

From Heat lost = Heat gained

c × (136.88)g°C = 12.708036 J

c = 12.708036 J / 136.88 g°C

c = 0.0928 J/g°C

Average specific heat capacity of metal = (0.8083 + 0.8039 + 0.0928) J/g°C / 3

Average specific heat capacity of metal = 0.57 J/g°C

Answer:

where is the quantities?

Answer:

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Answer:

The order is:

F >Be >Li >Ba

Explanation:

Electrons are held in atoms by their  attraction to the nucleus which means that to remove an electron from the atom energy is needed.

The ionization energy is the minimum energy necessary to remove an electron from an atom in the gas phase and ground state, the electron removed being the outermost, that is, the furthest from the nucleus. The further away the electron is from the nucleus, the easier it is to remove it, that is, the less energy is needed.

By increasing the atomic number of the elements of the same group, the nuclear attraction on the outermost electron decreases, since the atomic radius increases. Then the ionization energy decreases. In other words, in a group it decreases from top to bottom because the size of the atom increases and it is easier to remove an external electron.

By increasing the atomic number of the elements of the same period, the nuclear attraction on the outermost electron increases, since the atomic radius decreases. Therefore, in a period, as the atomic number increases, the ionization energy increases. In summary, in a period it increases from left to right as the effective nuclear charge increases and it increases thanks to the decrease in the size of the atom.

Taking these considerations into account, the order is:

F >Be >Li >Ba

The question is incomplete, the complete question is;

Cesium-137 is radioactive and has a half life of 30. years. Calculate the activity of a 6.8 mg sample of cesium-137. Give your answer in becquerels and in curies. Round your answer to 2 significant digits Bq Ci

Answer:

See explanation

Explanation:

The formula for activity is;

R= 0.693N/t1/2

N= 6.02 ×10^23 mol × 6.8 ×10^-3g/137 g/mol = 3 × 10^19

Substituting into the formula;

R= 0.693 × 3 × 10^19/30 years

R= 6.93 ×10^17 y^-1

In Bq;

6.93 ×10^17 y^-1 × 1.00y/3.16 ×10^7 seconds

= 2.19 ×10^10 Bq

In Ci;

2.19 ×10^10 Bq/3.7 ×10^10 Bq/Ci

= 0.59 Ci

Answer:

59.8 g of PbSO₄.

Explanation:

The balanced equation for the reaction is given below:

Pb + PbO₂ + 2H₂SO₄ —> 2PbSO₄ + 2H₂O

Next, we shall determine the mass of PbO₂ that reacted and the mass of PbSO₄ produced from the balanced equation. This can be obtained as follow:

Molar mass of PbO₂ = 207 + (16×2)

= 207 + 32

= 239 g/mol

Mass of PbO₂ from the balanced equation = 1 × 239 = 239 g

Molar mass of PbSO₄ = 207 + 32 + (16×4)

= 207 + 32 + 64

= 303 g/mol

Mass of PbSO₄ from the balanced equation = 2 × 303 = 606 g

SUMMARY:

From the balanced equation above,

239 g of PbO₂ reacted to produce 606 g of PbSO₄.

Finally, we shall determine the mass of PbSO₄ that will be produced by the reaction of 23.6 g of PbO₂. This can be obtained as follow:

From the balanced equation above,

239 g of PbO₂ reacted to produce 606 g of PbSO₄.

Therefore, 23.6 g of PbO₂ will react to produce = (23.6 × 606) / 239 = 59.8 g of PbSO₄.

Thus, 59.8 g of PbSO₄ were obtained from the reaction.

C₁₀H₁₄N₂ is the empirical formula of the compound whose mass is 40.57 present in 0.2500 moles.

Alkaloid compounds are those naturally present organic compounds in which nitrogen is present.

First we calculate the molecular mass of wanted compound by using the below formula:

n = W/M, where

n = no. of moles = 0.2500 moles (given)

W = given mass = 40.57 grams (given)

M = molar mass = 40.57 grams/= 0.2500 moles = 162.28 g/mole

In the question, given that:

% composition of carbon = 74.02%

% composition of hydrogen = 8.710%

% composition of nitrogen = 17.27%

Now we calculate the mass of these composition by using the below formula:

Composition mass = compound mass * % composition / 100

Mass of carbon = 162.28 * 74.02 / 100 = 120.11g

Mass of hydrogen = 162.28 * 8.710 / 100 = 14.13g

Mass of nitrogen = 162.28 * 17.27 / 100 = 28.02g

Now we calculate the moles of these composition to made empirical formula as:

Moles of carbon = 120.11 / 12 = 10

Moles of hydrogen = 14.13 / 1 = 14

Moles of nitrogen = 28.02 / 14 = 2

Thus, the empirical formula of the compound is C₁₀H₁₄N₂.

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Answer:

See explanation

Explanation:

The equation of the reaction is;

C3H8 + 5O2 ----> 3CO2 + 4H2O

Number of moles of C3H8 = 132.33g/44g/mol = 3 moles

1 mole of C3H8 yields 3 moles of CO2

3 moles of C3H8 yields 3 × 3/1 = 9 moles of CO2

Number of moles of oxygen = 384.00 g/32 g/mol = 12 moles

5 moles of oxygen yields 3 moles of CO2

12 moles of oxygen yields 12 × 3/5 = 7.2 moles of CO2

Hence C3H8 is the limiting reactant.

Mass of CO2 produced = 9 moles of CO2 × 44 g/mol = 396 g of CO2

1 moles of C3H8 yields 4 moles of water

3 moles of C3H8 yields 3 × 4/1 = 12 moles of water

Mass of water = 12 moles of water × 18 g/mol = 216 g of water

b) Actual yield = 269.34 g

Theoretical yield = 396 g

% yield = actual yield/theoretical yield × 100/1

% yield = 269.34 g /396 g × 100

% yield = 68%

We know

[tex]\boxed{\Large{\sf M_1V_1=M_2V_2}}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=\dfrac{M_1V_1}{V_2}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=\dfrac{3(75)}{250}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=\dfrac{225}{250}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=0.9M[/tex]

Answer:

Mass 1=3M

Mass 2=?

Volume1=75mL

Volume2=250mL

By using molarity formula:

mass1*volume 1=mass2*volume 2

3M*75=mass2*250

mass2=225/250

mass2:0.9M

Lester Brown thinks reducing carbon dioxide emissions 80% by 2050 is not fast enough.

Lester Brown is an American environmentalist who has focused on studying the environment and its protection. In recent years, he has made alerts for world leaders and large industries to strive to stop CO2 emissions because this greenhouse gas has a massive influence on global warming.

Therefore, Lester Brown considers that the projections of reduction of greenhouse gases (especially CO2) made by the world powers for the year 2050, ignore the reality because he considers that CO2 emissions must decrease by at least one 80% in 2020 to avoid drastic consequences in current living conditions. Therefore, the answer is B.

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Answer:

Spontaneous processes are ones that occur quickly and have a low activation energy. - False -

Spontaneous processes always require an input of energy to overcome the activation energy, but always react quickly - False

Spontaneous processes can occur slowly, but always have a low activation- false

Spontaneous reactions can react slowly and can have a high activation energy - True

Spontaneous processes always react slowly and always have a high activation energy- False

Explanation:

A spontaneous reaction is reaction that proceeds on its own without us having to do a thing at all!

A spontaneous reaction may be fast or slow depending on the activation energy of the reaction. A spontaneous reaction having a high activation energy will be slow. However, if the spontaneous reaction has a low activation energy then it will be fast.

We have to note here that a spontaneous reaction proceeds without a prolonged input energy. Sometimes energy may be supplied to the reaction at the beginning for instance in the case of the combustion of hydrocarbons.

So, spontaneous processes are not necessarily fast. Some of them may have a very high activation energy such as in the rusting of iron hence they are slow.

Answer:

Time is 2.2 seconds.

Explanation:

Time:

[tex]{ \boxed{ \bf{time = \frac{distance}{speed} }}}[/tex]

Substitute into the formula:

speed = 715 km/h = 198.61 m/s

[tex]{ \tt{time = \frac{435}{198.61} }} \\ { \tt{time = 2.2 \: seconds}}[/tex]

Trả lời:3 5-dimethylheptane

Explanation:

Answer

The properties of fatty acids and of lipids derived from them are markedly dependent on chain length and degree of saturation. Unsaturated fatty acids have lower melting points than saturated fatty acids of the same length. For example, the melting point of stearic acid is 69.6°C, whereas that of oleic acid (which contains one cis double bond) is 13.4°C. The melting points of polyunsaturated fatty acids of the C18 series are even lower. Chain length also affects the melting point, as illustrated by the fact that the melting temperature of palmitic acid (C16) is 6.5 degrees lower than that of stearic acid (C18). Thus, short chain length and unsaturation enhance the fluidity of fatty acids and of their derivatives.

Answer:

See explanation

Explanation:

We must first write the equation of the reaction as follows;

C3H8 + 5O2 ----> 3CO2 + 4H2O

Now;

We obtain the number of moles of C3H8 = 132.33g/44g/mol = 3 moles

So;

1 mole of C3H8 yields 3 moles of CO2

3 moles of C3H8 yields 3 × 3/1 = 9 moles of CO2

We obtain the number of moles of oxygen = 384.00 g/32 g/mol = 12 moles

So;

5 moles of oxygen yields 3 moles of CO2

12 moles of oxygen yields 12 × 3/5 = 7.2 moles of CO2

We can now decide on the limiting reactant to be C3H8

Therefore;

Mass of CO2 produced = 9 moles of CO2 × 44 g/mol = 396 g of CO2

Again;

1 moles of C3H8 yields 4 moles of water

3 moles of C3H8 yields 3 × 4/1 = 12 moles of water

Hence;

Mass of water = 12 moles of water × 18 g/mol = 216 g of water

In order to obtain the percentage yield from the reaction, we have;

b) Actual yield = 269.34 g

Theoretical yield = 396 g

Therefore;

% yield = actual yield/theoretical yield × 100/1

Substituting values

% yield = 269.34 g /396 g × 100

% yield = 68%

Answer:

There is no difference between the two.

Explanation:

They both show the same volume. But, adding decimal places shows the least count of the instrument used and is more acceptable when recording values in scientific experiments

Answer:

"[tex]N^+(g) \rightarrow N^{2+}(g) + e^-[/tex]" is the appropriate answer.

Explanation:

Thus the above is the correct answer.

Answer:

Tapeworms and roundworms both belong to the same phylum however, their families are different from one another.

Tapeworms are flat, segmented intestinal parasites of the cat and dog and humans sometimes. They are present in the intestines of pets and depend on them, therefore, are parasites. These parasites look like tape which gives it its name.

Roundworms can also infect humans and the most common cases are among children. When not treated immediately, they can cause severe damage to a human host and can even cause blindness. Tapeworms are white in color with a long, segmented body.

Answer:

catenation

Explanation:

Carbon atoms have four electrons to share in bonding environments to get to the ideal octet. To do this, it bonds with other carbon molecules, called catenation. Catenation is the ability of an atom to bond and share electrons with other atoms of its kind.

Answer:

Sorry but I know only what ksf stand for

Explanation:

Ksf stand for solubility product constant

Answer:

ksp stands for solubility product constant .

kf stands for molal freezing point depression constant ..

Explanation:

KSP = The solubility product constant, Ksp​, is the equilibrium constant for a solid substance dissolving in an aqueous solution. It represents the level at which a solute dissolves in solution. The more soluble a substance is, the higher the Ksp value it has .

KF = Kf is a constant for a given solvent. Kf is called the molal freezing point depression constant and represents how many degrees the freezing point of the solvent will change when 1.00 mole of a nonvolatile nonionizing (nondissociating) solute dissolves in one kilogram of solvent.

Answer:

2.21% wt/v

Explanation:

The mass/volume percentage, %wt/v, is an unit of concentration used in chemistry defined as 100 times the ratio of the mass of solute in g (In this case, CaCl2 = 1.77g) and the volume of solution in mL = 80mL

The %wt/v of this solution is:

%wt /v = 1.77g / 80mL * 100

%wt/v = 2.21% wt/v

Answer:

x= 300m , 38s

answer is 7.9

Answer:

speed=distance/time

Explanation:

speed=300/38

=7.8947368421

to the nearest tenth=7.9