Plz solve mcqs#04 with full detailed.note

Answer:

The correct option is;

The reaction pathway for the trials is different

Explanation:

The effect of a catalyst in a chemical reaction is to increase the rate of a reaction by changing the pathway or mechanism of the reaction and/or to lower the transition state's energy thereby lowering the activation energy of the reaction

The pathway of the reaction is changed by the catalyst by the formation of intermediate compounds by the catalyst which require lower activation energy to form the products than the original non-catalyzed reactants. In the process the catalyst is regenerated, thereby, not taking part in the reaction.

Answer:

25 g

Explanation:

Mass percent implies the mass of solute dissolved in a solution

Mass percent = mass of solute/mass of solute + mass of solvent × 100/1

Since mass percent concentration= 20%

Mass of solvent = 100g

Let mass of solute = x

Hence;

20 = x/x +100 ×100/1

20/100= x/x + 100

0.2 = x/x + 100

0.2(x + 100) = x

0.2x + 20 = x

20 = x - 0.2x

20 = 0.8x

x= 20/0.8

x= 25 g

Explanation:

pH is used to measure the concentration of H+ ions ([H+]) and therefore, whether a substance is acidic or basic (alkaline). Solutions with a pH of less than seven are acidic, while those with a pH greater than seven are basic (alkaline).

Answer:

greater than 7

Explanation:

A base is any solution with a pH greater than 7. A pH of 7 is considered neutral. For example, the pH of water. An acid is any solution with a pH less than 7.

Hope that helps.

Answer:

See explanation

Explanation:

Charles law gives the relationship between volume and temperature of a gas. Charles law States that, the volume of a given mass of gas is directly proportional to its temperature at constant pressure.

Theoretically, it is assumed that when the absolute zero temperature has been achieved, the volume of any ideal gas will be found to be equal to zero. If the volume of the gas is zero, it now implies that all molecular motion will be stopped. This does not happen in real gases as all gases are found to condense to solids or liquids when this temperature is exceeded.

When volume is plotted against temperature, volume of the gas approaches zero at t = −273.15 °C, which is the x-intercept of the Charles law graph. Below this temperature, we can only get negative values of volume which does not exist hence, −273.15 °C is the lowest attainable temperature also known as the absolute zero.

Answer:

Concept of chemi-fluorescence

Explanation:

A glow stick usually consists of two chemicals in a larger plastic tube: , a base catalyst (mostly sodium salicylate), and a suitable dye (sensitizer, or fluorophor). This creates an exergonic reaction when mixed together.

When a glow stick is bent, the flurophor which is a chemical that easily re-emits light upon excitation in smaller capsules is released into the other substance, there by causing it to emit radiation/light in the uv-visible region. The brightness and longevity of the glow stick is determined by varying the concentration of these chemicals.

I hope this explanation clarifies things.

[tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]  is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .

The rate at which the concentration of reactant or product participating in a chemical reaction alters is called the rate of reaction.

Rate of reaction = [tex]\frac{change \;in \;concentration}{time}[/tex] =  (mol/litre)/time.

m= 1 and n = 2

[tex]rate = K [A] [B]^2[/tex]

[tex]0.2 = K X 3 X 3 ^2[/tex]

K =   [tex]\frac{0.2 }{27 }[/tex]

K =   [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]

Hence, [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]  is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .

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Answer: 7.4 10-3

Explanation:

7.4 10-3 this is right ong

Answer:

balanced equation:

2Ca(NO3)2 (aq)-----> 2CaO (s) + 4NO2 (g) + O2 (g)

So heating 2 moles of Ca(NO3)2 gives 2 moles of CaO, 4 moles of NO2 and 1 mole of O2. This is a heat decomposition reaction. It gives a white precipitate (CaO), and brown pungent gas (NO2).

Answer:

The balanced equation of the reaction is below.

Explanation:

2Ca(NO3)2 -----> 2CaO + 4NO2 + O2.

Answer:

A

Explanation:

civil deals with desighning, construction work of natural or physical environment and a fits guess

Answer:  [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde functional group.

Explanation:

Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

A.  [tex]CH_3CH_2CH_2COCH_3[/tex] has ketone [tex]C=O[/tex] functional group .

B.  [tex]CH_3CH_2CH_2COOH[/tex] has carboxylic acid [tex]COOH[/tex] functional group .

C.  [tex]CH_3CH_2CH_2CHO[/tex] has  aldehyde [tex]H-C=O[/tex] functional group .

D. [tex]CH_3CH_2CH_2COOCH_3[/tex] has ester [tex]RO-C=O[/tex] functional group .

Thus [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde (CHO) group.

Answer:

Option B. K = 1.3×10⁴, product favored

Explanation:

Data obtained from the question include:

O2(g) + 2SO2(g) <==> 2SO3(g)

Concentration of O2, [O2] = 0.024 M

Concentration of SO2, [SO2] = 0.015 M

Concentration of SO3, [SO3] = 0.26 M

Equilibrium constant, K =..?

The equilibrium constant, K is simply defined as the ratio of the concentration of products raised to their coefficient to the concentration of the reactants raised to their coefficient.

The equilibrium constant for the above reaction can be written as

K = [SO3]² / [O2] [SO2]²

Inputing the values of [SO3], [O2] and [SO2] the equilibrium constant, K is:

K = [SO3]² / [O2] [SO2]²

K = 0.26² / 0.024 × 0.015²

K = 1.3×10⁴

Therefore, the equilibrium constant K is 1.3×10⁴.

Since the value of the equilibrium constant, K is large and positive, therefore, the reaction favours the product.

Answer:

D. two-stroke cylinder engine.

Explanation:

Two-stroke cylinder engine: In chemistry, the term "two-stroke cylinder engine" is described as one of the types of "internal combustion engine" that tends to complete a single "power cycle" possessing two different strokes of the "piston" during a particular "crankshaft revolution".

It generally consists of two different strokes that are being often known as power or exhaust and suction stroke.

In the question above, the given statement signifies the "two-stroke cylinder engine".

Answer:

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Explanation:

Let's start by counting how many molecules we have on each side.

Reactants

C - 5

H - 12

O - 2

Products

C - 1

O - 3

H - 2

We have to balance both sides. Since we have 5 carbon atoms on the reactants side and 1 carbon atom on the products side, we'll start with that. Write 5 as the coefficient for CO₂ to balance the carbons.

C₅H₁₂ + O₂ → 5CO₂ + H₂O

Now that the carbons are balanced, let's look at the hydrogens. There's 12 on the reactants side and 2 on the products side. To balance the hydrogens, we have to write 6 as the coefficient for H₂O.

C₅H₁₂ + O₂ → 5CO₂ + 6H₂O

Now the hydrogens are balanced. All that's left to do is balance the oxygens. Let's start by counting how many atoms we have on each side.

Reactants

C - 5

H - 12

O - 2

Products

C - 5

H - 12

O - 16

So, to balance the number of atoms on both sides, write 8 as the coefficient for O₂.

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Lastly, let's check to make sure everything is balanced.

Reactants

C - 5

H - 12

O - 16

Products

C - 5

O - 16

H - 12

Both sides are balanced. Therefore, the balanced chemical equation is: C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O.

Hope that helps.

Answer:

[tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]

Explanation:

Part 1: Count the number of atoms on each side per element

To start, count the number of atoms per element on both sides of the equation.

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 1 atom

H - 2 atoms

O - 3 atoms

Part 2: Balance carbon atoms

Now, with this information, you can begin finding out how to properly balance both sides of the equation.

You need 5 carbon atoms on the left, so place a coefficient of 5 in front of the [tex]CO_{2}[/tex] product. This will balance the carbons. Do not place a coefficient in front of the [tex]C_{5}H_{12}[/tex] reactant - none are necessary!

Then, you can update your counts for your atoms.

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 5 atoms

H - 2 atoms

O - 11 atoms

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12}+O_{2} --> 5CO_{2} + H_{2}O}[/tex]

Part 3: Balance hydrogen atoms

Now, balance the hydrogen atoms. Place a coefficient of 6 in front of the [tex]H_{2}O[/tex] product. This will balance the hydrogen atoms.

Once again, update the atom counts:

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 5 atoms

H - 12 atoms

O - 16 atoms

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12} +O_{2}--> 5CO_{2} +6H_{2}O}[/tex]

Part 4: Balance oxygen atoms

To fully balance the equation, place a coefficient of 8 in front of the [tex]O_{2}[/tex] reactant. This will equalize the amount of oxygen atoms on both sides of the equation.

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12} + 8O_{2} --> 5CO_{2} + 6H_{2}O}[/tex]

Part 5: Check the equation and atom counts

Now, update the atom counts one last time to make sure they are equal.

Left Side

C - 5 atoms

H - 12 atoms

O - 16 atoms

Right Side

C - 5 atoms

H - 12 atoms

O - 6 atoms

They are equal, so you may proceed.

Part 6: Check if reductions are necessary

If the equations coefficients can all be divided by a common divisor (i.e., 3), follow up with that step. However, any equation that has a reactant or product without a coefficient, skip this step entirely.

This equation falls into that category, so you may proceed past it.

Your final equation will look like this: [tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]

Answer:

The solubility of KCl is 1.93 mol/dm³

Explanation:

The information given are;

The mass of the potassium chloride, KCl = 144 g

The volume of the water solvent = 1000 cm³ = 1 dm³

The temperature of the solvent = 90 °C

The atomic mass of potassium, K = 39 u

The atomic mass of chlorine, Cl = 35.5 u

The number of moles of potassium in one mole of potassium chloride, KCl = 1 mole

The number of moles of chlorine in one mole of potassium chloride, KCl = 1 mole

The molar mass of the potassium chloride = 39 + 35.5 = 74.5 g/mol

The number of moles, n, of potassium chloride, KCl in 144 g of potassium chloride, KCl is given as follows

n = Mass/(Molar mass) = 144/74.5 = 1.93 moles

1.93 moles will dissolve in 1 dm³

Therefore, the solubility of KCl is 1.93 mol/dm³.

Answer:

d

Explanation:

i got it right

Gas A is likely to have the lowest temperature.  Hence, option A is correct.

The smallest particle of a substance has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.

In a gas, the kinetic energy is directly proportional to the temperature under constant pressure and volume.

As you can see in the problem, the average of A has low kinetic energy. But the average is increasing between B, C and D.

As gas A has the lowest average kinetic energy:

Gas A is likely to have the lowest temperature

Hence, option A is correct.

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Answer:

the melting point T = 125.36°C

Explanation:

Given that:

The resistance of a platinum thermometer at  0°C is  [tex]R_o[/tex] = 160.0 ohms

The resistance of a platinum thermometer when immersed in a crucible containing a melting substance [tex]R_t[/tex] = 243.8 ohms

The temperature coefficient at room temperature  20°C = ∝ = 0.00392

The objective is to determine the melting point of this substance

To do that ; at 20°C, the resistance of the platinum thermometer can be calculated as follows:

[tex]R_{20} = R_o(1 + \alpha \Delta T)[/tex]

[tex]R_{20} = 160(1 + (0.00392 \times (20-0)^0C))[/tex]

[tex]R_{20} = 160(1 + (0.00392 \times (20))[/tex]

[tex]R_{20} = 160(1 + (0.0784)[/tex]

[tex]R_{20} = 160(1.0784)[/tex]

[tex]R_{20} = 172.544 \ ohms[/tex]

The resistance of the platinum thermometer at t°C , [tex]R_t[/tex] = [tex]R_{20}(1 + \alpha \Delta T)[/tex]

[tex]243.8 = 172.544(1 + 0.00392 \times (T-20)^0C}[/tex]

[tex]\dfrac{243.8}{ 172.544 }= (1 + 0.00392 \times (T-20)^0C}[/tex]

[tex]1.413 = (1 + 0.00392 \times (T-20)^0C}[/tex]

[tex]1.413-1 = 0.00392 \times (T-20)^0C}[/tex]

[tex]0.413 = 0.00392 \times (T-20)^0C}[/tex]

[tex]\dfrac{0.413 }{0.00392} = (T-20)^0C}[/tex]

105.36°C = (T - 20) °C

T = 105.36°C + 20 °C

T = 125.36°C

Answer:

Explanation:

Electrochemical cells primarily comprise of two half-cells. These half-cells assist in isolating the oxidation and reduction half-reactions. These two reactions are linked by a wire which allows the current to move from one edge to the other. The oxidation at the anode and the reduction take place at the cathode and the addition of a salt bridge helps in completing the circuit and permits the current to flow and leads to the generation of electricity.

Answer:

oppositely charged ions in a chemical compound

Explanation:

Answer:

Between ions

Explanation:

Answer:

A large point of evidence in this would be the rate of increase in how fast the polar ice caps are melting and the ocean is rising as a result. As the climate is getting warmer so are the oceans and this is causing the ice caps which are in the ocean.

Explanation:

Answer:

Here's what I get from one source.

Explanation:

[tex]\begin{array}{lc}\textbf{Source} &\textbf{Contribution \%} \\\text{Space heating }& 45\\\text{Water heating} &18\\\text{Space cooling} & 9 \\\text{Computers/Electronics} & 6 \\\text{Lighting} & 6 \\\text{Cooking} & 4 \\\text{Refrigeration} & 4 \\\text{Wet cleaning} & 3 \\\text{Other} & 5 \\\end{array}[/tex]

The pie chart is in the Figure below.

The single mark placed on the sidewalk by Julie has been acting as the reference point for detecting the motion of the snail. Thus, option D is correct.

The snail has been the shelled animal that has been mostly residing in the resting condition with limited movement. To evaluate the movement of the snail, there has been the consideration of a point that was the starting point from the movement.

The line that has been set across the sidewalk has been acting as the reference, and the distance traveled has been calculated from that point. Thus, option D is correct.

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Answer:

The chemical bond between 2 molecules is called an intermolecular force.

Answer:

Chemical Bond:

Attraction between two atoms results in the formation of a bond which is called a chemical bond.

Inter molecular Forces:

Attractive Force that in between 2 molecules is called Inter molecular Forces. (Inter : Between)

Answer:

The statement that describes an electron is "It has a negative charge and is located in orbitals around the nucleus." Electrons are the smallest of the three particles that make up atoms

Explanation:

Electrons are found in shells or orbitals that surround the nucleus of an atom

Electrons are the sub-atomic particles that carry a negative charge over them. In the atom, the electrons are found in the orbitals or the shells around the nucleus. Thus, option D is correct.

Electrons are the smallest sub-atomic particle that has been known to carry a negative charge and are found in the orbitals of the atom. The charge carried by an electron is 1.602 x 10⁻¹⁹ coulomb and is small than the proton and neutron.

They revolve around the nucleus in their orbits and exhibit the properties of waves and matter. The number of electrons and protons are the same in a neutral atom which makes the atomic number.

Therefore, the electrons have been known to carry a negative charge that revolves in orbit around the nucleus.

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Your question is incomplete, but most probably your full question was, Which statement describes an electron?

Answer:

if your eyes are exposed to a hazardous chemical you should use the eye wash station. The first few seconds after exposure to a hazardous chemical are critical.

Answer:

0.020g de sulfato de plomo se requieren

La concentración de la solución diluida es de 3ppm

Explanation:

Las partes por millón (ppm) son definidas como:

miligramos soluto / 1L solución.

Si deseas preparar una solución a 100ppm de sulfato de plomo (II) necesitas 100mg de este sulfato en 1L. En 200mL = 0.200L vas a necesitar:

0.200L × (100mg / 1L) = 20mg de sulfato de plomo (II).

Como 1000mg = 1g,

20mg × (1g / 1000mg) = 0.020g de sulfato de plomo se requieren.

Ahora, se van a tomar 30mL de esta solución y se diluirán a 1000mL. Se diluye la solución:

1000mL / 30mL = 33.33 veces.

Como la solución inicial es de 100ppm, esta dilución genera una solución de concentración:

100ppm / 33.33 = 3ppm

Answer:

The acid solution is a concentrated solution.

Explanation:

Acetic acid is a weak acid, because it ionizes partially in water as shown below:

CH3COOH + H2O —> H3O+ + CH3COO-

A solution containing a larger quantity of acetic acid is termed concentrated solution.

This is so because a concentrated solution is a solution that contains more of the solute than the solvent.

A solute is the substance which dissolves in the solvent.

A solvent is the substance which dissolves a solute.

In this case, acetic acid is the solute and water is the solvent.

Solution is simply the combination of solute and solvent

Solution => Solute + Solvent

More solute + Less solvent => Concentrated solution

Therefore, a solution containing a higher quantity of acetic acid ( i.e the solute) in water (i.e the solvent) is called a concentrated solution.

Answer:

The correct options are;

C. Divergent plate boundary

D. Normal faults

Explanation:

Tensile stress tends to pull objects part by acting axially upon the object to pull the object on a cross section perpendicular to the objects cross-section

The most common stress in convergent plate boundaries is compression stress

The most common stress in divergent plate boundaries is tensile stress

In the presence of tensile stress, normal faults results in the raising of mountains due to their enormous forces

Therefore, the features of Earth's crust involving tension are divergent plate boundary and normal faults.

Answer:c and d

Explanation:

Answer:

Na3 Po4

Explanation:

Na+1

Na+1

Na+1 = Na3

Po4 =

Na3Po4

Na[tex]_3[/tex]Po[tex]_4[/tex] is the formula for sodium phosphate. Sodium phosphates have a wide range of uses in food and water treatment.

Sodium phosphate is indeed a catch-all phrase for a number of sodium (Na+) as well as phosphate (PO43) salts. Phosphate also forms di-, tri-, tetra-, as well as polyphosphate families or condensed anions. The majority of these salts exist across both anhydrous (water-free) as well as hydrated forms. Hydrates are more prevalent than anhydrous forms.

Sodium phosphates have a wide range of uses in food and water treatment. Sodium phosphates, for example, are frequently employed particularly emulsifying agent (as in processed cheese), smoothing agents, especially leavening agents in baked products. Na[tex]_3[/tex]Po[tex]_4[/tex] is the formula for sodium phosphate.

Therefore, Na[tex]_3[/tex]Po[tex]_4[/tex] is the formula for sodium phosphate.

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Answer:

[tex]\boxed{\mathrm{Iodine}}[/tex]

Explanation:

Halogens are elements in group 17 or 7 in the periodic table.

Iodine is a halogen.

Therefore, iodine, an Halogen

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Answer:

Chemical Changes are also called Chemical Reactions. Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions.

Explanation:

Answer:

A.

Explanation:

Higher temperature - more kinetic energy - more space between particles - higher volume.