Classify the changes involved in the following processes as physical or chemical changes: (a) Photosynthesis (b) Dissolving sugar in water (c) Burning of coal (d) Melting of wax (e) Beating aluminium to make aluminium foil (f) Digestion of food

Answer:

You are not supposed t9 be cheating

Explanation:

Answer:

ΔT = 0.116 °C

Explanation:

Using Formula

Q = mc ΔT

Where Q = 0.360, c = 4.184 and m = 0.7402

ΔT = Q/mc

ΔT = 0.360/ (4.184)(0.7402)

ΔT = 0.360 / 3.097

ΔT = 0.116 °C

So, The change in Temperature/Increase in Temperature is 0.116 °C

Answer:

split the reaction in to respective ions to ge the ionic equation of this reaction

Explanation:

2 Al + 2Fe+3  O3^-2 ---> 2Al+3 O3^-2  + 2Fe

ins simple it would be

Al   + Fe+3     ----> Al+3   + Fe

Answer:

B. H2SO4 + BaCl 2 --------> BaSO4 + 2HCl

Explanation:

Neutralization reactions are characterized by their reactants of acids and bases reacting to form salt and water. All of the options except B, have formation of salt and water. Also, B is more likely a percipitation reaction (also a double displacement reaction) and not neutralization.

Answer:

64.9 L

Explanation:

pls mark as brainliest

Answer:

The required volume of water the student needs is 4.9 litres of water

Explanation:

From the diagram related to the question, we have;

The dimensions of the tank are;

Length of tank = 24.0 cm = 0.24 m

Width of tank = 21.0 cm = 0.21 m

Depth of tank = 13.0 cm. = 0.13 m

Allowance provided between the top of the tank and the top of the water = 2.0 cm

Diameter of the round bottom flask, D = 10.5 cm = 0.105 m

Therefore, the radius of the round bottom flask, r = 0.105/2 = 0.0525 m

Therefore we have;

Depth of water in the tank = Depth of tank - Allowance provided between the top of the tank and the top of the water

∴ Depth of water in the tank = 13.0 - 2.0 = 11.0 cm = 0.11 m

Given that the flask is immersed in the water contained in the tank to raise the tank water level, we have;

Volume of water + Volume of flask in the tank = Length of tank × Width of tank × Depth of water in the tank

Volume of water + Volume of flask in the tank =  0.24 × 0.21 × 0.11 = 0.005544 m³ = 0.005544 m³× 1000 l/m³ = 5.544 l

The volume of the spherical flask = 4/3·π·r³ = 4/3·π·0.0525³ = 6.06×10⁻⁴ m³ = 6.06×10⁻⁴ m³ × 1000 l/m³ = 0.606 l

The required volume of water the student needs , V = Volume of water + Volume of flask in the tank - The volume of the spherical flask = 5.544 l - 0.606 l = 4.9 l.

Answer:

a. 0.02 moles  of NH₃, 0 moles of O₂, 0.08 moles of NO, 0.12 moles of H₂O

b. [tex]P_{NH_3}[/tex] = 12,576.5 Pa, [tex]P_{NO}[/tex] = 50,306.05 Pa, [tex]P_{H_2O}[/tex] =  74,459.1 Pa

c. The total pressure is 138,341.64 Pa

Explanation:

a. NH₃ + O₂  → NO + H₂O

The balanced chemical equation is first found to be

4NH₃ + 5O₂  → 4NO + 6H₂O

Therefore, we have;

4 moles of NH₃ reacts with 5 moles of O₂ to form 4 moles of NO and 6 moles H₂O

Dividing by the reactant with the highest number of moles which is 5 moles of oxygen gives;

4/5 moles  of NH₃ reacts with 5/5 moles of O₂ to form 4/5 moles of NO and 6/5 moles H₂O

Which is the same as 4/5 moles  of NH₃ reacts with 1 mole of O₂ to form 4/5 moles of NO and 6/5 moles H₂O

Multiplying by 0.100 gives;

0.1×4/5 moles  of NH₃ reacts with 0.1 mole of O₂ to form 0.1×4/5 moles of NO and 0.1×6/5 moles H₂O

The quantity of each gas in the container upon completion of the reaction is therefore;

(0.1 - 0.1×4/5) = 0.02 moles  of NH₃

0 moles of O₂

0.08 moles of NO

0.12 moles H₂O

b. Given that the temperature = 105°C, we have;

PV = nRT

P = nRT/V

Where:

n = Total number of moles = 0.02 + 0.08 + 0.12 = 0.22 moles

R = Universal gas constant = 8.3145 J/(mol·K)

T = Temperature = 105°C = 378.15 K

V = Volume = 5 litre = 0.005 m³

P = 0.22×8.3145×378.15/0.005 = 138,341.64 Pa

From Dalton's law of partial pressure, we have;

Partial pressure Pₓ = Xₓ × P

Where:

Xₓ = Mole fraction

Which gives for ammonia NH₃ with 0.02 moles;

Mole fraction = 0.02/0.22 = 1/11

[tex]P_{NH_3}[/tex] = 1/11 × 138,341.64  = 12,576.5 Pa

For the 0.08 moles of NO, we have

Mole fraction = 0.08/0.22 = 4/11

[tex]P_{NO}[/tex] = 4/11 × 138,341.64  = 50,306.05 Pa

For the 0.12 moles H₂O

P = 0.12×8.3145×378.15/0.005 = 74,459.1 Pa

Mole fraction = 0.12/0.22 = 6/11

[tex]P_{H_2O}[/tex] = 6/11 × 138,341.64  = 74,459.1 Pa

c. The total pressure = 12,576.5 Pa + 50,306.05 Pa + 74,459.1 Pa = 138,341.64 Pa.

Answer:

Sodium sulfide is the chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both the anhydrous and the hydrated salts are colorless solids. They are water-soluble, giving strongly alkaline solutions. When exposed to moist air, Na2S and its hydrates emit hydrogen sulfide, which smells like rotten eggs. Some commercial samples are specified as Na2S·xH2O, where a weight percentage of Na2S is specified. Commonly available grades have around 60% Na2S by weight, which means that x is around 3. Such technical grades of sodium sulfide have a yellow appearance owing to the presence of polysulfides. These grades of sodium sulfide are marketed as 'sodium sulfide flakes'.

Contents

1 Structure

2 Production

3 Reactions with inorganic reagents

4 Uses

4.1 Reagent in organic chemistry

5 Safety

6 References

Structure

Na2S adopts the antifluorite structure,[2][3] which means that the Na+ centers occupy sites of the fluoride in the CaF2 framework, and the larger S2− occupy the sites for Ca2+.

Production

Industrially Na2S is produced by carbothermic reduction of sodium sulfate often using coal:[4]

Na2SO4 + 2 C → Na2S + 2 CO2

In the laboratory, the salt can be prepared by reduction of sulfur with sodium in anhydrous ammonia, or by sodium in dry THF with a catalytic amount of naphthalene (forming sodium naphthalenide):[5]

2 Na + S → Na2S

Reactions with inorganic reagents

The sulfide ion in sulfide salts such as sodium sulfide can incorporate a proton into the salt by protonation:

S2−

+  H+ → SH−

Because of this capture of the proton ( H+), sodium sulfide has basic character. Sodium sulfide is strongly basic, able to absorb two protons. Its conjugate acid is sodium hydrosulfide (SH−

). An aqueous solution contains a significant portion of sulfide ions that are singly protonated.

S2−

+ H

2O {\displaystyle {\ce {<=>>}}}{\displaystyle {\ce {<=>>}}} SH−

+  OH−

(1)

SH−

+ H

2O {\displaystyle {\ce {<<=>}}}{\displaystyle {\ce {<<=>}}} H

2S +  OH−

(2)

Sodium sulfide is unstable in the presence of water due to the gradual loss of hydrogen sulfide into the atmosphere.

When heated with oxygen and carbon dioxide, sodium sulfide can oxidize to sodium carbonate and sulfur dioxide:

2 Na2S + 3 O2 + 2 CO

2 → 2 Na2CO3 + 2 SO2

Oxidation with hydrogen peroxide gives sodium sulfate:[6]

Na2S + 4 H2O2 → 4 H

2O + Na2SO4

Upon treatment with sulfur, polysulfides are formed:

2 Na2S + S8 → 2 Na2S5

Uses

Sodium sulfide is primarily used in the kraft process in the pulp and paper industry.

It is used in water treatment as an oxygen scavenger agent and also as a metals precipitant; in chemical photography for toning black and white photographs; in the textile industry as a bleaching agent, for desulfurising and as a dechlorinating agent; and in the leather trade for the sulfitisation of tanning extracts. It is used in chemical manufacturing as a sulfonation and sulfomethylation agent. It is used in the production of rubber chemicals, sulfur dyes and other chemical compounds. It is used in other applications including ore flotation, oil recovery, making dyes, and detergent. It is also used during leather processing, as an unhairing agent in the liming operation.

Reagent in organic chemistry

Alkylation of sodium sulfide give thioethers:

Na2S + 2 RX → R2S + 2 NaX

Even aryl halides participate in this reaction.[7] By a broadly similar process sodium sulfide can react with alkenes in the thiol-ene reaction to give thioethers. Sodium sulfide can be used as nucleophile in Sandmeyer type reactions.[8] Sodium sulfide reduces1,3-dinitrobenzene derivatives to the 3-nitroanilines.[9] Aqueous solution of sodium sulfide can be refluxed with nitro carrying azo dyes dissolved in dioxane and ethanol to selectively reduce the nitro groups to amine; while other reducible groups, e.g. azo group, remain intact.[10] Sulfide has also been employed in photocatalytic applications.[11]

Explanation:there you go

When sodium combines with sulphur, it formed sodium sulphide. When it interacts with sulfur, polysulfides are produced. Additionally, heat causes sodium sulfide to oxidize fast. Sulfur dioxide and sodium carbonate are the end products.

Chemical element sulfur has the letter S and atomic number 16. It is multivalent, nonmetallic, and plentiful. Sulfur atoms normally combine to create cyclic octatomic molecules, which have the chemical formula S₈.

At room temperature, elemental sulfur is a crystalline solid that is brilliant yellow. It is employed in the production of fertilizer, water treatment, mineral extraction, oil refining, and automobile batteries.

Other uses for compounds based on sulfur include vulcanizing rubber, bleaching paper, and producing goods like cement, detergents, and insecticides.

Thus, When sodium combines with sulphur, it formed sodium sulphide.

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Answer:

Sodium is stored under kerosene because of its high chemical reactivity with almost all of other elements (for example oxygen from air which oxidizes it instantly). Kerosene and mineral oil are the only chemicals that make the sodium inert. Usually when Na reacts with a solvent it liberates hydrogen gas from its composition.

Explanation: Just saying , I want to be honest. I copied and pasted this from google

Answer:

Yes it does change

Explanation:

Answer:

Iron is oxidized to form rust.

Explanation:

Consider the reaction; 4Fe + 302------>2Fe2O3, we can see that iron is being oxidized to iron III oxide. Rust is the common name of iron III oxide.

Rusting is an electrochemical process, iron rusts when it comes into contact with air and water because electrochemical cells are set up at the surface of contact.

Iron usually functions as the anode in the electrochemical process. This process leads to the formation of iron III oxide. Rust is soft and breaks off easily thereby exposing the metal below the surface to further rusting.

Answer:

Iron is oxidized to form rust.

Explanation:

edge

The chemical equation for the given word equation is Ca(OH)[tex]_2[/tex](S) + 2HCI(I) → CaCl[tex]_2[/tex](aq) + 2H[tex]_2[/tex]0(1).   Therefore, the correct option is option D.

Chemical equations are symbols or chemical formulas that depict a chemical reaction symbolically. With a plus sign separating the entities in the reactants and products, the reactant objects are listed on the left as well as the result entities are listed on the right.

An arrow indicating the reaction's direction points in the path of the products. The chemical formulas could be mixed, symbolic, or structural. The critical values of a stoichiometric figures are shown as coefficients beside the symbols as well as formulas of the various entities. The chemical equation for the given word equation is Ca(OH)[tex]_2[/tex](S) + 2HCI(I) → CaCl[tex]_2[/tex](aq) + 2H[tex]_2[/tex]0(1).  

Therefore, the correct option is option D.

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Answer:

See below.  

Explanation:

1. Newton's first law

(a) Problem 1

What is the net force required to keep a 500 kg object moving with a constant velocity of 10 m·s?

Answer: None.

Explanation: An object in motion stays in motion unless a net force acts on it.

The object will keep moving at 10 m/s.

(b) Problem 2

A force of 20 N acts on a 10 kg object from the left. A force of 30 N acts on it from the right. What is the net force required to keep the object moving with a constant velocity of 10 m/s?

Answer: 20 N

Explanation:  

The net force is

30 N - 20 N = 10 N

You must apply another 10 N from the left. The net force is then:  

30 N - 30 N = 0

If there is no net force, the object will keep moving at 10 m/s.

2. Newton's second law

(a) Problem 1

What is the net force needed to accelerate an object at a constant 5 m·s⁻²?

Answer: 5 N

Explanation:

F = ma = 1 kg × 5 m·s⁻² = 5 kg·m·s⁻² = 5 N

(a) Problem 2

A net force of 2 N acts on a 1 kg object.  What is the magnitude and direction of the acceleration?

Answer: 2 m·s⁻²

Explanation:

F = ma

2 N = 1 kg × a

a = (2 N)/(1 kg) = (2 kg·m·s⁻²\1 kg) = 2 m·s⁻²

The direction of the acceleration is the same as that of the applied force.

2. Newton's third law

(a) Problem 1

A person with a mass of 58 kg is standing near you. Diagram and calculate the opposing forces.

Answer: 570 N up and down

Explanation:

See Fig. 1.  The person's mass exerts a downward force on the floor.

F = mg, where g is the acceleration due to Earth's gravity

F = 58 kg × 9.8 m·s⁻² = 570 kg·m·s⁻² = 570 N

The floor exerts an upward force of 570 N.

(a) Problem 2

A teacher (mass 65 kg) pushes a cart (mass = 12 kg) of equipment (mass = 7 kg). Her foot applies a force of 150 N backward on the floor against a frictional force of 24 N. Diagram the opposing forces and calculate the net force available to move the cart.

Answer: 126 N

Explanation:

See Fig. 2 below. The teacher's mass exerts a downward force W on the floor, which exerts an equal reaction force R upward. The cart and equipment also exert a downward force on the floor, which exerts the same force upward. We can ignore these forces because they do not contribute to forward motion.

The teacher's foot exerts a backward force of 150 N on the floor, which exerts an equal force forward. However, a frictional force of 24 N opposes the forward force.

The net external force is the force of the floor minus the opposing frictional force. Thus,

F = 150 N − 24 N = 126 N

Answer:

A part.

Explanation:

Because the reactants must be the exact same as the the products.

Answer:

The answer is lemonade.

Weaker acids are those which tend to have a higher pH from 4 to at least 6 stronger acids have low pH from 2 and below that's from 2 to 0.

Hope this helps

Hope

Answer: [tex]Zn+2Ag^+\rightarrow Zn^{2+}+2Ag[/tex]

Explanation:

Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously and the number of electrons lost is equal to the number of electrons gained.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.

Anode : [tex]Zn\rightarrow Zn^{2+}+2e^-[/tex]

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

Cathode : [tex]2Ag^++2e^-\rightarrow 2Ag[/tex]

Thus the complete ionic equation will be :

[tex]Zn+2Ag^+\rightarrow Zn^{2+}+2Ag[/tex]

Answer:

P = 2,8,3

q = 2,8,6

Explanation:

Because the first shell contain 2 electron and the 2nd contain 8 electron and the last shell contain the electron which is left

Explanation:

p=1s^2,2s^2,2p^6,3s^2,3p^1

q=1s^2,2s^2,2p^6,3s^2,3p^4

the quantum numbers are used in my answer.

there are 4 quantum numbers.

1.principal quantum numbers

2.angular momentum quantum numbers

3.magnetic quantum numbers

4.spin quantum numbers

In this case,the angular momentum quantum numbers is being used.it describes the unique quantum state of an electron and is designated by the letter L.this behaviour manifests itself as the shape of the orbital.electron shells have distinct shapes denoted by letters,s,p,d,f.

l can be numbers like,0,1,2,3

the maximum electrons in each letter is,

s=2

p=6

d=10

f=14

the shapes of the sub_shells

s sub_shell is spherical

p sub_shell is two dumb_bells

d sub_shell is four dumb_bells

f sub_shell is eight dumb_bells

Answer: Light

Explanation:

The environment abiotic factors like sunlight, water, air, and soil are important for the growth of the plants. A wildflowers is a plant that grows in wild. It was not intentionally seeded or planted.

The light is one of the important environmental factor. As the wildflowers are blooming earlier than the large trees. Thus the wildflowers are receiving the light earlier than large trees.

Answer: D convection currents

Explanation:

The seafloor spreading is a phenomena that occurs due to liberation of heat from the convection currents generated in the mantle. It makes the earth crust more plastic and less dense. This happens at divergent plate boundaries. As the plates move apart, the less denser material rises. It leads to the formation of mountain and crust cracks.

pH = 0.35

Explanation: hope this helps

Answer: 0.35

Explanation:

Answer:

reactants : before arrow sign

: CH4 and O2

product : after arrow sign

: CO2 and H2O

the answer is the second option

Answer:

Mineral water> Bitter gourd juice> Orange juice> Hydrochloric acid

Explanation:

pH is referred to as the degree of acidity or alkalinity of a substance. The pH scale is arranged from 0-14. Substance with a pH of 0-6.9 are acid, a pH of 7 indicates neutrality while a pH of 8-14 indicates alkalinity.

Mineral water is usually slightly acidic with a pH between 5-6. The pH of bitter gourd juice is between 4.24-4.45. The pH of orange juice ranges between 3.3 to 4.2 lastly, the pH of hydrochloric acid is about 3.01.

The pH values itemized above informed the arrangement of decreasing pH values shown in the answer box.

Answer:

Genetic tagging, or the identification and tracking of individual animals using DNA, is a non-invasive method of conducting research that uses samples from shed hair, feathers, feces, or saliva. ... Genetic tagging approaches are complementary to traditional approaches and add a powerful tool to the ecologists' toolkit."

Explanation:

Answer:

Troposphere

Explanation:

The troposphere is the lowest layer in the atmosphere, and where all the weather occurs. After the troposphere, there's the stratosphere, mesosphere, thermosphere, and exosphere.

I hope this helps!

Answer:

Troposphere is the lowest layer of the earths atmosphere.

Explanation:

Answer:

B

Explanation:

Option be is the only molecular structure with 4 carbon molecules and 10 hydrogen molecules

Answer:

The statement "The total mass of hydrochloric acid and sodium hydroxide will result in the same total mass of sodium chloride and water." is true due to the Law of Conservation of Mass which states that matter cannot be created nor destroyed.

The correct answer to the question is: The total mass of hydrochloric acid and sodium hydroxide will result in the same total mass of sodium chloride and water.

Chemical equation is backed up by the law of conservation of matter (mass) which states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to the other.

Thus,

The total mass of reactants is equal to the total mass of products.

For example: let us consider the reaction between hydrogen and oxygen to produce water

2H₂ = 2(2×1) = 2(2) = 4 g

O₂ = 2 × 16 = 32 g

2H₂O = 2[(2×1) + 16]

= 2[2 + 16]

= 2[18]

Thus,

From the above illustration, we can conclude that the total mass of hydrochloric acid and sodium hydroxide will result in the same total mass of sodium chloride and water.

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Answer:

what are the options

Explanation:

there are no options

SO₃ is an empirical formula for S₂O₆ and the correct option is option C.

The empirical formula of a compound represents the simplest, most reduced ratio of the atoms present in the compound. It shows the relative number of atoms of each element in the compound, without indicating the actual number of atoms. In other words, it gives the simplest whole number ratio of the elements in a compound.

To determine the empirical formula, the relative amounts of each element in the compound are expressed in terms of moles or mass. Then, the ratios of the moles or masses are simplified to their lowest whole number values.

Thus, the ideal selection is option C.

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The complete question is -

SO₃ is an empirical formula for which of the following?

A. S₄O₂

B. SO₄

C. S₂O₆

D. S₂O₃