Label each of the following changes as a physical change or chemical change. Give evidence to support your answer.


A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas

Answer:

It's a representative metal

Explanation: Transitional metals are metals of various chemical elements and have valence electrons—i.e., electrons that can participate in the formation of chemical bonds.

Answer:

The answer is D - Atom

The smallest unit of an element that can exist either alone or in combination with other such particles of the same or different elements is the atom.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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Answer:

See explanation

Explanation:

Number of moles of naphthalene = 0.32g/128.1705 g/mol = 0.0025 moles

Molality = number of moles/ mass of Solvent in kilograms

Molality = 0.0025/0.025 Kg

Morality = 0.1 m

But

∆T= K × i × m

Where ∆T = boiling point elevation

i= number of particles (this is equal to 1 because naphthalene is molecular and not ionic)

m= molality of naphthalene = 0.1 m

K= boiling point elevation constant = 5.12 °C/m

∆T= 5.12 °C/m ×0.1 = 0.512°C

For freezing point depression

∆T= K× i × m

Where ∆T= freezing point depression

i= number of particles (this is equal to 1 because naphthalene is molecular and not ionic)

m= molality of naphthalene = 0.1 m

K= freezing point depression constant = 2.67 °C/m

∆T= 2.67 °C/m ×0.1 = 0.267°C

From Raoult's law;

∆P = XBPA°

Where;

∆P = vapour pressure lowering

XB = mole fraction of solute

PA° = vapour pressure of pure solvent

Number of moles of solvent = mass/molar mass = 25g/ 78 g/mol= 0.3205 moles

Total number of moles = number of moles of solute + number of moles of solvent = 0.0025 moles + 0.3205 moles = 0.323 moles

Mole fraction of solute = 0.0025 moles/0.323 moles = 0.0077

Vapour pressure of benzene = 100 torr

Therefore;

∆P = 0.0077 × 100torr = 0.77 torr

Hence;

∆P = 0.77 torr

Answer:

0.013 mol/L

Explanation:

Molarity, which is molar concentration or moles per unit volume, can be calculated using the formula:

M = n/V

Where; M = Molar concentration of solution

n = number of moles of solute

V = Volume of solvent

n = 0.0025 moles of sugar

V = 200.00mL of solution

Since 0.001L = 1mL

200mL = 0.200L

Therefore, M = n/V

M = 0.0025/0.200

M = 0.0125 mol/L

Round up to the nearest thousandth ~ 0.013mol/L

Answer:

Linear molecule with two domains

Explanation:

Answer:

Arsenic.

Explanation:

Hello there!

In this case, since insecticides are substances that act as poisons to get rid of insects in order to prevent their presence and/or reproduction in houses, companies, crops and others, a substance that has been widely used is the metalloid arsenic due to its direct affection of the insect's body (movement, performance, cellular functions).

In addition, high levels of arsenic in food could cause arsenic poisoning in humans as well, that is why such practice must be properly performed and by using the correct security protocol.

Best regards!

Answer:

As

Explanation:

hoffe das hilf jedem in der zukunft

Answer:

Kindly check the explanation section.

Explanation:

Without mincing words let us dive right into the solution to the question above, taking each compound at a time.

NB: Kindly Check attachment for the Lewis Structure of each of the chemical compounds.

Therefore, the number of valence electrons, electronic shape, molecular shape and whether the molecules are polar(Polarity) is given below for each chemical compound.

(1). Compound: HCN

(a). number of valence electrons = 10.

(b). electronic shape =linear.

(c). molecular shape = linear.

(d). Polarity = Y.

(2). Compound: PH3

(a). number of valence electrons = 8.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Trigonal Pyramidal.

(d). Polarity = Y.

(3). Compound: CHCl3.

(a). number of valence electrons = 26.

(b). electronic shape = tetrahedral.

(c). molecular shape = tetrahedral.

(d). Polarity = Y.

(4). Compound: NH4^+

(a). number of valence electrons = 8

(b). electronic shape = tetrahedral

(c). molecular shape = tetrahedral

(d). Polarity = Y.

(5). Compound: H2CO

(a). number of valence electrons = 12.

(b). electronic shape = Trigonal planar.

(c). molecular shape = Trigonal planar

(d). Polarity = Y.

(6). Compound: SO4^2-

(a). number of valence electrons = 32.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Tetrahedral.

(d). Polarity = N.

(7). Compound: SeF2.

(a). number of valence electrons = 20.

(b). electronic shape = Tetrahedral.

(c). molecular shape = bent.

(d). Polarity = Y.

(8). Compound: CO2.

(a). number of valence electrons = 16.

(b). electronic shape = linear.

(c). molecular shape = linear.

(d). Polarity = N.

(9). Compound: O2

(a). number of valence electrons = 32.

(b). electronic shape = Trigonal planar.

(c). molecular shape = Linear.

(d). Polarity = N.

(10). Compound: ClO4-.

(a). number of valence electrons = 32.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Tetrahedral.

(d). Polarity = N.

(11). Compound: HBr.

(a). number of valence electrons = 8.

(b). electronic shape = Linear.

(c). molecular shape = Linear.

(d). Polarity = Y.

(12). Compound: PF5.

(a). number of valence electrons = 40.

(b). electronic shape = Trigonal Bipyramidal.

(c). molecular shape = Trigonal Bipyramidal.

(d). Polarity = N.

(13). Compound: BeH2.

(a). number of valence electrons = 4.

(b). electronic shape = Linear.

(c). molecular shape = Linear.

(d). Polarity = N.

(14). Compound: PO4^3-.

(a). number of valence electrons = 32.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Tetrahedral.

(d). Polarity = N.

(15). Compound: BH3.

(a). number of valence electrons = 6.

(b). electronic shape = Trigonal planar.

(c). molecular shape = Trigonal planar.

(d). Polarity = N

(16). Compound: Br3-.

(a). number of valence electrons = 32.

(b). electronic shape = Trigonal Bipyramidal.

(c). molecular shape = Linear.

(d). Polarity = N.

Answer:

The disruption of the bonds or attractions occurs during protein hydrolysis which results in the loss for the primacy structure. The peptide bonds is the bond affected in this scenario.

The disruption of the bonds however only exist in the process of denaturation and this results in a change in the confirmation which could be secondary, tertiary, and quaternary structural related. And example of the bonds affected include salt bridges, disulfide bridges, hydrogen bonds etc.

Answer:

strong base

Explanation:

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Answer:

d

Explanation:

Answer:

In carbon dioxide, on the right, there is 2.666 g of oxygen for every gram of carbon. So the ratio of oxygen in the two compounds is 1:2, a small whole number ratio

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Answer:

The electrons are found on the outer shell of the atom.

Explanation:

Answer:

plucking is usually extracting hair

Explanation:

example: pluck the chicken feathers

pluck my brows

Answer:

What mass of sodium hydroxide is needed to react completely with 10.0 g of iron( III) chloride? The conversion sequence is: A. B.

Explanation:

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Answer:

Explanation:The ether functional group consists of an oxygen atom that forms single bonds with two carbon atoms

Answer:

Yes, but it must be kept at that value and do not let it to decrease more.

Explanation:

Hello.

In this case, in order to substantiate whether the cabin meet the federal standards, we need to convert the 500 mmHg to atm and compare the result with 0.72 atm by knowing that 1 atm equals 760 mmHg:

[tex]500mmHg*\frac{1atm}{760mmHg} \\\\=0.66atm[/tex]

Thus, since 0.66 atm is 0.06 atm away from the federal standard we can infer that it may meet the federal standard, however, it would not be recommended to let the pressure decrease more than that.

Yes, the cabin pressurized at 500 mm hg meets federal standards.

1 atm is approximately equal to 760 mm Hg. Therefore, the pressure is:

500 mm Hg / 760 mm Hg/atm ≈ 0.65789 atm

So, the cabin pressure of 500 mm Hg is approximately 0.65789 atmospheres. If the atmospheric pressure at an elevation of 8000 feet averages about 0.72 atmospheres, then the cabin pressure of 0.65789 atmospheres would be lower than the ambient atmospheric pressure.

To meet federal standards, cabin pressure should be maintained at an equivalent pressure that allows occupants to breathe comfortably.

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Answer:

53/26Fe = 0/-1,B + 53/27 Co

Answer:

The answer is 7.89

Explanation:

Mass of methane required to increase the temperature of the air in the room by 7.35 °C is 7.95 g

The volume of air in the room is first calculated:

Volume of air in the room = 4.33 m x 3.43 m x 3.03 = 45.00 m³

1 m³ = 1000 L

45.00 m³ = 45.00 m³ * 1000 L/m³

Volume of air in L = 45000 L

Number of moles of air in 45000 L of air is then determined:

1.00 moles of air occupies 22.4 L

number of moles of air in 45000 L = 45000 L * 1 mole / 22.4 L

number of moles of air = 2008.93 moles of air

Energy that is needed to heat the room by 7.35 °C is then calculated:

Quantity of energy needed = Specific heat capacity * number of moles * temperature increase

Specific heat capacity of air = 30.0 J/K/mole

Quantity of energy needed = 30.0 * 2008.93 * 7.35

Quantity of energy needed = 442969.065 J = 443.00 kJ

The amount of methane required to produce that amount of energy is then calculated:

Equation of combustion of methane : CH₄ + 2 O₂  ---> CO₂ + 2 H₂O

Enthalpy of combustion of methane = −890.3 kJ/mole

Number of moles of methane required = 443.00 kJ / 890.8 kJ/mole = 0.497 moles

Mass of 1 mole of methane = 16.0 g

mass of 0.497 moles of methane = 16.0 * 0.497 = 7.95 g

Therefore, mass of methane required to increase the temperature of the air in the room by 7.35 °C is 7.95 g

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Answer:

The molecular formula of the hydrocarbon is C10H10

Explanation:

Here, we are interested in finding the molecular formula for the hydrocarbon.

Since there are equal number of moles of carbon and hydrogen, then we have the molecular formula looking like;

CnHn

Kindly recall that the atomic mass of carbon is 12 a.m.u while that of hydrogen is 1 amu

so calculating the atomic mass of the compound, we have;

12(n) + 1(n) = 130.18

13n = 130.18

n = 130.18/13

n = 10.01

So the molecular formula will be C10H10

Answer:

C10H10

Explanation:

A hydrocarbon is a binary compound of carbon and hydrogen. Hence a hydrocarbon is a compound of the general formula (CH)n

Thus;

(12 + 1) n = 130.18

n= 130.18/13

n = 10

Hence the molecular formula of the compound is C10H10

Answer:

рн

Explanation:

From the given choices, pH is the only chemical property that can be measured quantitatively.

A chemical property is one that tells us about what a substance can do as regards to whether or not the substance reacts with other substances.

Examples are flammability, rusting of iron, precipitation, decomposition of water e.t.c

Answer:

The answer is

[tex] \huge 7.40 \times {10}^{21} Hz[/tex]

Explanation:

To find the frequency of the wave we use the formula

[tex]f = \frac{E}{h} \\ [/tex]

where

E is the energy

f is the frequency

h is the Planck's constant which is

6.626 × 10-³⁴ Js

From the question

E = 4.90 × 10-¹² J

So we have

[tex]f = \frac{4.90 \times {10}^{ - 12} }{6.626 \times {10}^{ - 34} } \\ [/tex]

We have the final answer as

[tex]7.40 \times {10}^{21} \: \: Hz[/tex]

Hope this helps you

Answer:

Explanation:

Fe⁺²(aq) + ClO₂(aq) → Fe⁺³(aq) + ClO₂⁻(aq)

Here oxidation number of Fe is increased from +2 to +3 , so Fe is oxidised .

The oxidation number of Cl is reduced from + 4 to +3  so Cl is reduced .

So ClO₂(aq) is oxidising agent and Fe⁺²(aq) is reducing agent .

Answer:

def compute_volume(pressure,moles,temperature):

    volume = (8.314 * moles * temperature)/pressure

    print("Volume: "+str(volume))

Explanation:

This line defines the function

def compute_volume(pressure,moles,temperature):

This line calculates the volume

    volume = (8.314 * moles * temperature)/pressure

This line prints the calculated volume

    print("Volume: "+str(volume))

Answer:

266Lr

Thirteen isotopes of lawrencium are currently known; the most stable is 266Lr with a half-life of 11 hours, but the shorter-lived 260Lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale.

Explanation:

hopefully that helps you

Explanation:

heat

the presence of hot, plastic like material

Explanation:Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance. Heat increases when these particles move faster. Geothermal energy is the thermal energy in the earth. Motion energy is energy stored in the movement of objects.

I hope this helped!