evidence of a chemical change includes?

Answer:

.743 g/mL

Explanation:

Hopefully this helps :)

Answer:

The answer is 60W

Power = Work done/ time

time = 1 second

Work done = 60J

Power = 60/1

= 60W

Hope this helps.

Answer:

La B

Explanation:

It's B on Ap3x

Straight away from the source

Answer:

1) 1.39 grams H2O2

2) 0.933 grams Fe

Explanation:

Step 1: Data given

Volume of oxygen = 0.460 L

STP = 1 atm and 273 K

Step 2: The balanced equation

2H2O2(aq) → 2H2O(l) + O2(g)

Step 3: Calculate the number of moles O2

p*V = n*R*T

⇒with p= the pressure = 1 atm

⇒with V = the volume = 0.460 L

⇒with n = the number of moles = TO BE DETERMINED

⇒with R = the gas constant = 0.08206 L*atm/mol*K

⇒with T = the temperature = 273 K

n = (p*V)/(R*T)

n = (1 * 0.460)/ (0.08206*273)

n = 0.0205 moles moles

Step 4: Calculate moles H2O2

For 2 moles H2O we'll have 2 moles H2O and 1 mol O2

For 0.0205 moles O2 we'll need 2*0.0205 = 0.041 moles H2O2

Step 5: Calculate mass H2O2

Mass H2O2 = moles H2O2 * molar mass H2O2

Mass H2O2 = 0.041 moles * 34.01 g/mol

Mass H2O2 = 1.39 grams

Step 1: Data given

Volume of hydrogen = 0.500 L

STP = 1 atm and 273 K

Step 2: The balanced equation

3Fe(s) + 4H2O(l) → Fe3O4(s) + 4H2(g)

Step 3: Calculate the moles of H2

p**V = n*R*T

⇒with p= the pressure = 1 atm

⇒with V = the volume = 0.500 L

⇒with n = the number of moles = TO BE DETERMINED

⇒with R = the gas constant = 0.08206 L*atm/mol*K

⇒with T = the temperature = 273 K

n = (p*V) / '*T)

n = (1 * 0.500) / (0.08206 * 273)

n = 0.0223 moles

Step 4: Calculate moles Fe

For 3 moles Fe we need 4 moles H2O to produce 1 mol Fe3O4 and 4 moles H2

For 0.0223 moles H2 we'll need 0.0223 *3/4 = 0.0167 moles Fe

Step 5: Calculate mass of Fe

Mass Fe = moles Fe * atomic mass Fe

Mass Fe = 0.0167 moles * 55.845 g/mol

Mass Fe = 0.933 grams Fe

1. The mass of the hydrogen peroxide should be 1.39 grams H2O2.

2) The mass of the iron should be 0.933 grams Fe.

Since

Volume of oxygen = 0.460 L

STP = 1 atm and 273 K

Now The balanced equation

2H2O2(aq) → 2H2O(l) + O2(g)

Now the number of moles O2

p*V = n*R*T

Here p= the pressure = 1 atm

V = the volume = 0.460 L

n = the number of moles = ?

R = the gas constant = 0.08206 L*atm/mol*K

T = the temperature = 273 K

Now

n = (p*V)/(R*T)

n = (1 * 0.460)/ (0.08206*273)

n = 0.0205 moles moles

Now  moles H2O2 should be

For 2 moles H2O we'll have 2 moles H2O and 1 mol O2

So,

For 0.0205 moles O2 we'll need 2*0.0205 = 0.041 moles H2O2

Now mass H2O2

Mass H2O2 = moles H2O2 * molar mass H2O2

Mass H2O2 = 0.041 moles * 34.01 g/mol

Mass H2O2 = 1.39 grams

2. The mass of the iron should be

Since

Volume of hydrogen = 0.500 L

STP = 1 atm and 273 K

Now

The balanced equation

3Fe(s) + 4H2O(l) → Fe3O4(s) + 4H2(g)

Now the moles of H2

p**V = n*R*T

Here

p= the pressure = 1 atm

V = the volume = 0.500 L

n = the number of moles = ?

R = the gas constant = 0.08206 L*atm/mol*K

T = the temperature = 273 K

So,

n = (p*V) / '*T)

n = (1 * 0.500) / (0.08206 * 273)

n = 0.0223 moles

Now Calculate moles Fe

For 3 moles Fe we need 4 moles H2O to produce 1 mol Fe3O4 and 4 moles H2

So,

For 0.0223 moles H2 we'll need 0.0223 *3/4 = 0.0167 moles Fe

Now the mass of Fe

Mass Fe = moles Fe * atomic mass Fe

Mass Fe = 0.0167 moles * 55.845 g/mol

Mass Fe = 0.933 grams Fe

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Answer: D. 4,6,4

Explanation:

The valence electron is the electron found in the outermost shell of an atom, and participates in bond formation.

For the following element, the valence electron can be noticed when we write the electronic configuration of each element.

Silicon =  1s2 2s2 2P6 3s2 3p2

Sulphur = 1s2 2s2 2P6 3s2 3p4

Germanium =  1s2 2s2 2P6 3s2 3p6 3d10 4s2 4p2

Answer: C.) Xe

Explanation: To figure out the answer go to the Noble Gas Family and count down 5 elements.

According to the electronic configuration the symbol which would be included in the noble gas notation for an element that had valence electrons in the 5 s subshell is xenon  .

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

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A) 4

pH=-log[H+]

pH=-log(10^-4)

B) Weaker

pH of orange juice=4

pH of coffee=5

An acid with pH of 4 is stronger than a pH of 5

C) 7, neither/neutral

pH of water=7

Answer:

(a) Formation of the carbocation is the rate-determining step (RDS)

(c) Reactions at chiral carbons proceed with inversion of stereochemistry

Explanation:

SN1 reactions arenucleophilic substitution reactions in which the rate determining step is unimolecular.

The formation of a carbocation is the rate determining step. This depends on the electrophilicity of the leaving group. Thus the SN1 reaction mechanisms is dependent on the electrophile and not the nucleophile.

Polar and acidic solvents which can assist in the formation of the carbocation speeds up the rate determining step.

If the formation of carbocation occurs at a chiral center, both retention and inversion of stereochemistry are likely to occur.

Therefore, the correct options are A and C.

Answer:

Tornadoes form when warm, humid air collides with cold, dry air.

Explanation:

The denser cold air is pushed over the warm air, usually producing thunderstorms. The warm air rises through the colder air, causing an updraft. The updraft will begin to rotate if winds vary sharply in speed or direction.

// have a great day //

Answer:

your question says of the following but their isn't any of the following ):

Explanation:

But other than than that person right up above

Answer:

SO4^2- is the oxidizing agent.

l^- is the reducing agent.

Explanation:

SO4^2- + I^- + H^+ —> H2S + I2 + H2O

To know which is the oxiding agent or the reducing agent, let us calculate the change in oxidation number of each element. This is illustrated below:

Note: the oxidation number of Hydrogen (H) is always +1 except in hydride where it is -1.

The oxidation number of Oxygen (O) is always -2 except in peroxide where it -1

For S:

SO4 = -2

S + 4O = -2

O = - 2

S =.?

S + (4 x -2) = -2

S - 8 = -2

Collect like terms

S = -2 + 8

S = +6

H2S = 0

2H + S = 0

H = +1

S =..?

2(1) + S = 0

2 + S = 0

Collect like terms

S = 0 - 2

S = -2

The oxidation number of S changes from +6 to -2

For I:

I = - 1

I = 0

The oxidation of I changes from -1 to 0.

Since the oxidation number of S changes from +6 to -2 i.e reduce, therefore SO4^2- is the oxidizing agent.

The oxidation number of I changes from -1 to 0 ie increased. Therefore, l^- is the reducing agent.

In a galvanic cell, the oxidation and reduction of metals occurs at the electrodes. There are two electrodes in a very cell, one in each half-cell. The cathode is where reduction takes place and oxidation takes place at the anode.

Answer:

Tests for unsaturation involves addition across the multiple bonds in the unsaturated compound.

Explanation:

In organic chemistry, we define an unsaturated compound as any compound that contains a double or triple bond. These multiple bonds are also known as pi bonds.

There are two major tests for unsaturation which shall both be discussed here.

The first test for unsaturation is by the use of bromine water. The unknown sample is passed through a solution of bromine water which normally appears reddish brown. The bromine water becomes decolorized due to addition of bromine across the multiple bond. This is a standard test for unsaturation.

Secondly, unsaturated compounds decoulourize a solution of potassium permanganate when passed through it. This alone can not be used as a distinctive test for unsaturation.

Propenoic acid will give a positive test to the both reagents showing that it contains multiple bonds, in this particular instance, a double bond.

Answer:

7.8

Explanation:

pH + pOH = 14

pOH = 14 - 6.2

= 7.8

Answer: Using a dry tea towel to grab a hot pan puts the heat into the towel fibers, which are poor conductors of heat, and which serve to separate your hand from the hot pan by a set of air gaps.

A dry towel is a better insulator than a wet towel. Because the water in the wet towel fills the empty spaces between the fibers of the towel and helps to conduct heat. Therefore, it is much safer to pick up hot dishes with a dry cloth than a wet one.

Conduction can be described as the process by which heat is transferred from the hotter to the colder end of an object. The capability of the object to conduct heat is its thermal conductivity.

Heat flows along a temperature gradient. Heat is conducted from the hot plate of a stove to the bottom of a saucepan in contact with it, which is an example of thermal conduction.

In solids, conduction is the combination of vibrations and collisions of molecules, propagation and collisions, and diffusion of free electrons. In gases and liquids, conduction is due to the diffusion and collisions of molecules while their random motion. Therefore, thermal conduction will be faster in a wet towel than in a dry towel.

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Answer:

Mg(s)+Zn2+>>>>>Mg2++Zn(s) B

Explanation:

The net ionice quation of a reaction represents the net  change in the reaction.Here the reaction proceeds to the formation of Mg²⁺  ion and metallic zinc. Thus option B is correct.

What is ionic equation?

A balanced equation of chemical reaction represents the perfect stoichiometric ratio of each reactants and products where each elements have to be equal in number in both side.

An ionic equation represents the ions involved in the reaction and the charges and coefficients of ions have to balanced each side.

In the electrolysis of magnesium and zinc electrodes, metallic magnesium oxidizes to Mg²⁺ions and Zn²⁺ ions reduces to metallic zinc. The NO³⁻- ions remains as same as in its aqueous state in the electrolyte.

Hence the net ionic equation is as written in  option B.

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Answer: The IUPAC name of [tex]CH_3C\equiv CCH_2CH_2Cl[/tex] is 5-chloro-2-pentyne

Explanation:

1. First select the longest possible carbon chain.  For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.

2. The longest possible carbon chain should contain all the bonds and functional groups.

3. The numbering is done in such a way that the carbon containing the functional group or substituent gets the lowest number. Triple bond is given priority over substituent halogen.

4. The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne.

Thus the IUPAC name of [tex]CH_3C\equiv CCH_2CH_2Cl[/tex] is 5-chloro-2-pentyne

Answer:

Alkane

Alkene

Alkyne

Explanation:

Alkane=1 bond (Saturated hydrocarbon)

Alkene= 2 bonds (Unsaturated hydrocarbon)

Alkyne= triple bonds (Unsaturated hydrocarbon)

Formula of Alkane = CnH2n+2

Formula of Alkene = CnH2n

Formula of Alkyne = CnH2n-2

Answer:

0.077M is the concentration of the hydroxyl ion

Explanation:

Dilution factor is the ratio between the aliquot that is taken of a solution and the total volume of the diluted solution.

For the problem, dilution factor is:

7.53cm³ / 147cm³ = 0.05122

To obtain molarity of a diluted solution you must multiply dilution factor and initial molarity of the solution, thus:

1.5 M × 0.05122 = 0.077M is the concentration of the hydroxyl ion

Answer:

0.60 moles of Na₂SO₄

Explanation:

Molarity is an unit of concentration defined as the ratio between moles of solute and liters of solution.

A solution of Na₂SO₄ 0.40M contains 0.40 moles of solute (Na₂SO₄) per liter of solution.

As you have 1.5L of solution, moles of Na₂SO₄:

1.5L × (0.40mol / L) = 0.60 moles of Na₂SO₄

Answer:

False

Explanation:

This is because the electrical circuit, where the electrical energy is converted into another form of energy, e.g. lightbulb converts electrical energy into light and heat, an electric bell converts the electrical energy into sound and heat.

False.

The statement a load in a circuit transforms the light energy into electrical energy is False.

Any device which transforms the electrical energy into other forms of energy, like light energy, sound energy, etc is called an electric load in the circuit.

The type of kinetic energy caused by moving electric charges is known as electrical energy. The alternating current, direct current, and batteries provide electrical energy.

So, the load transforms the electrical energy into other forms like light energy, sound energy, etc.

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Answer:

Explanation:

The higher the melting point of a substance, then the higher the force of attraction. Which means there is direct relationship between the melting point and force of attraction.

The increasing order of interparticle force of attraction of the the three particles are

Z(398) Y(314) X (298)

I.e Particle " Z " have highest melting point, follows by particle "Y" follows by particle "X

NOTE: The melting point of a substance refers to the

temperature whereby there there is a change from solid state to liquid state, it is dependent on the pressure of the system

Answer:

C. Rate = k[H2]^2[O2]

Explanation:

Rate law only cares about REACTANTS. Since, rate law can only be determined experimentally, I am assuming the given reaction mechanism is elementary reaction from which we can write the rate law.

Only H2 and O2 are part of rate law since they are reactants and also the coefficient in front of H2 goes as exponent on rate law to indicate the order of H2 in the reaction.

Rate= k [H2]^2 [O2]

According to the chemical equilibrium, the rate law for the given reaction is Rate = k[H₂]²[O₂] as  the concentration is dependent on both the reactants.

Chemical equilibrium is defined as the condition which arises during the course of a reversible chemical reaction with no net change in amount of reactants and products.A reversible chemical reaction is the one wherein the products as soon as they are formed react together to produce back the reactants.

At equilibrium, the two opposing reactions which take place take place at equal rates and there is no net change in amount of the substances which are involved in the chemical reaction.At equilibrium, the reaction is considered to be complete . Conditions which are required for equilibrium are given by quantitative formulation.

Factors which affect chemical equilibrium are change in concentration , change in pressure and temperature and presence of catalyst.

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Answer:

ΔH° of the reaction is -747.54kJ

Explanation:

Based on gas law, it is possible to find the ΔH of a reaction using ΔH of half reactions.

Using the reactions:

(1) C(graphite) + 1/2O₂(g) → CO(g) ΔH° = -110.5 kJ

(2) CO(g) + 1/2O₂(g) → CO₂(g) ΔH° = -283.0 kJ

(3) H₂(g) + 1/2O₂(g) → H₂O(l) ΔH° = -285.8 kJ

(4) C(graphite) + 2H₂(g) → CH₄(g) ΔH° = -74.81 kJ

(5) CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) ΔH° = -890.3 kJ

The sum of 4×(4) + (5) gives:

4C(graphite) + 8H₂(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) + 3CH₄(g)

ΔH° = -74.81 kJ ×4 - 890.3 kJ = -1189.54kJ

Now, this reaction - 4×(1) gives:

4CO(g) + 8H₂(g) → CO₂(g) + 2H₂O(l) + 3CH₄(g)

ΔH° = -1189.54kJ - 4×-110.5 = -747.54kJ

Thus ΔH° of the reaction is -747.54kJ

ΔH° of the reaction is for the production of SNG -747.54kJ

According to Hess’ law of constant summation, the standard reaction enthalpy is independent of the pathway or number of the reaction steps taken for a multistep reaction, rather it is the sum of standard enthalpies of intermediate reactions involved at the same temperature.

Based on Hess law, it is possible to find the ΔH of a reaction using ΔH of half reactions.

From the given reactions:

The sum of Reaction 4 × 4 + Reaction 5 - Reaction 1 × 4 gives the reaction below:

4CO(g) + 8H₂(g) → CO₂(g) + 2H₂O(l) + 3CH₄(g)

ΔH° = {-74.81 kJ × 4} - 890.3 kJ {- 4 ×-110.5}

ΔH° = -747.54kJ

Therefore, ΔH° of the reaction is for the production of SNG -747.54kJ

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Answer:

The site at which the lander would have the greatest amount of gravitational potential energy is X

Explanation:

The formula for gravitational potential is given as follows;

[tex]PE_G = m \times g \times \Delta H[/tex]

Where:

g = Acceleration due to gravity

m = Mass of the lander

ΔH = Height above surface

Landing site --- Height above surface --- Acceleration due to gravity

W                        32                                    1.6

x                          16                                    3.7

Y                         35                                    1.6

Z                         12                                     3.7

Therefore, we have;

For site W

[tex]PE_G = m \times 1.6 \times 32 = 51.2 \cdot m[/tex]

For site X

[tex]PE_G = m \times 3.7 \times 16= 59.2 \cdot m[/tex]

For site Y

[tex]PE_G = m \times 1.6 \times 35 = 56 \cdot m[/tex]

For site Z

[tex]PE_G = m \times 3.7 \times 12 = 44.4 \cdot m[/tex]

Hence the site at which the lander would have the greatest amount of gravitational potential energy is X with [tex]PE_G[/tex] = 59.2·m.

Gravitational energy is the power stored in an object due to the intensity of gravity or because the article is located vertically.

The correct answer is:

The site at which the lander would have the greatest amount of gravitational potential energy is X.

The correct explanation for site X is:

The gravitational energy can be calculated as the product of mass, gravitational field and height.

[tex]{\text{PE}_{\text G}&= \text{m}\; \times\text g\times \Delta\text H[/tex]

Where,

Given,

Landing site        Height above surface              Gravity

    W                                    32                                    1.6

    X                                     16                                     3.7

    Y                                     35                                     1.6

    Z                                     12                                      3.7

We can calculate Gravitational energy for all the sites as follows:

       [tex]{\text{PE}_{\text G}&= \text{m}\; \times\ 1.6\times 32 = 51.2 \text \; \times \text {m}[/tex]

       [tex]{\text{PE}_{\text G}&= \text{m}\; \times\ 3.7\times 16 = 59.2 \text \; \times \text {m}[/tex]

       [tex]{\text{PE}_{\text G}&= \text{m}\; \times\ 1.6\times 35 = 56 \text \; \times \text {m}[/tex]

       [tex]{\text{PE}_{\text G}&= \text{m}\; \times\ 3.7 \times 12= 44.4 \text \; \times \text {m}[/tex]

Therefore, the greatest amount of gravitational energy 59.2m is present on-site X.

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Answer:

The answer is 80!

Explanation:

A prism is a three dimensional solid object in which the two ends are identical. It is the combination of the flat faces, identical bases and equal cross sections. The volume of the prism is 819 cm³.

A prism is a polyhedron with two parallel congruent faces called the bases that are polygons. The volume of a three dimensional solid is the amount of space it occupies. The volume is measured in cubic units. The volume can be denoted in m³, cm³, ft³, etc.

The volume of a prism is the area of the base times the height. The equation used to calculate the volume is:

Volume = Base area × Height

Here the rectangle has 9cm length and 7cm width. Then the area is:

Area = 9 × 7 = 63 cm²

The height of prism = 13 cm

Then the volume is:

V = 63 × 13 = 819 cm³

Thus the volume of the prism is 819 cm³.

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Your question is incomplete most probably your full question was

What is volume of the rectangular prism with length 9cm, width 7cm and height  13 cm?

Answer:

3. ethyne

Explanation:

Highest ratio of hydrogen to carbon? I'm not sure I found it on the internet but the answer is right

Answer:

gasoline

Explanation: