Please help me with number 12

Answer:

(i) rusting is caused by the reaction of oxygen and water on the surface of metals(iron).

(ii) rusting of iron makes it weak and dangerous for buildings since their foundation is made of iron, rusting renders cars useless, rusting can cause accidents.

(iii) by galvanizing iron

and by coating it.

Explanation:

hope it helps .

Answer:

80.07 g/mol

Explanation:

Sulfur's g/mol = 32.07

Oxygen's g/mol = 16.00

32.07 + 16.00(3) = 80.07 g/mol

Answer:

80.07 g/mol

Explanation:

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:

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:

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: 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.

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

Explanation:

a. chemical change

b. Physical change.

c. chemical change.

d. chemical change

e. Physical change.

f. chemical change.

Answer:

1.68 atm.

Explanation:

Given:

P1 = 4.23atm

V1 = 1870 mL

T1 = 293K

P2 = ?

V2 = 6.01 L = 6010 mL

T2 = 373 K

Assuming number of moles and R is constant:

[tex]\frac{P1V1}{T1} = \frac{P2V2}{T2}[/tex]

⇒ P2 = [tex]\frac{P1V1T2}{T1V2}[/tex] = [tex]\frac{2,950,467.3}{1,760,930}[/tex]

= 1.68 atm.

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:

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

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:

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:

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:

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:

A part.

Explanation:

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

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:

The displacement reactions are regarded as redox reactions because they involve the formal transfer of electrons from one chemical specie to the other

2) The series of reactivity of the metals in the order of increasing reactivity are;

           ↓

           ↓

Explanation:

1) Redox (oxidation-reduction) reaction is a chemical reaction involving the loss and gain of electrons from one chemical species to another, where the chemical species that undergoes oxidation, loses electrons and is termed the reducing agent, while the other chemical species that undergoes reduction, gains electrons, and is termed the oxidizing agent

2) The redox reaction can being based on the affinity for electrons depends on the positions of the reactants in the electrochemical series as well as the chemical reactivity of the metals with zinc being a stronger reducing agent and more chemically reactive than copper and magnesium being a stronger reducing agent and more chemically reactive than zinc

Least  reactive (Cu)  <     (Zn)        < Mg Most reactive

Copper                     <      Zinc       < Magnesium.

Answer:

Yes it does change

Explanation:

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:

The formation of a precipitate

Explanation:

took thecquiz on edge. got it correct

The formation of a precipitate is a evidence that a chemical reaction has likely occurred.

A chemical reaction is a process in which chemical bonds between atoms to break and reorganize, to form other new substances.

Now lets check all option one by one

Option (A): a liquid slowly losing volume

Here change in volume occurred which is not a evidence of a chemical reaction.

So it is incorrect option.

Option (B): the formation of a precipitate

Here formation of precipitate is a evidence of a chemical reaction.

So it is correct option.

Option (C): boiling water releasing steam

Here formation of evaporation takes places which is not a evidence of a chemical reaction.

So it is incorrect option.

Option (D): a change in the shape of solid.

Here change in shape occurred which is not a evidence of a chemical reaction.

So it is incorrect option.

Thus, from we can say that the formation of a precipitate is a evidence that a chemical reaction has likely occurred.

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Answer:

Advantage:

It forms ferrous oxide which is used as a pigment for glasses

Disadvantage:

It destroys the appearance of the metal and weakens it.

Answer:

Advantage: Rusting provides a thin durable shell to prevent the metal from getting more corroded.

Disadvantage: Rusting weakens material due to prolonged corrosive action.

Explanation:

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:

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

pH = 0.35

Explanation: hope this helps

Answer: 0.35

Explanation:

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.

What is pollen in the reproduction cycle of flowering plants?

A pollen grain is a microspore containing the male gametophyte, usually reduced to two undivided cells, each with one haploid (n) nucleus. These cells are surrounded by a very resistant wall, the exine, which generally has apertures, zones with less resistance which will allow the germination of the pollen tube.

Explanation of the reproduction cycle (cf diagram above)

A given species produces flowers bearing stamens. According to species, these flowers can be unisexual (stamens only) or bisexual (stamens and carpels).

The stamen anthers include 4 pollen sacs containing sporogenous cells (diploid=2n). These sporogenous cells undergo meiosis, each producing 4 microspores (haploid=n). Two nuclei are then formed by mitosis : the vegetative nucleus and the generative nucleus. The latter divides to form 2 sperms. Simultaneously the wall of the microspores becomes thicker and takes the characteristic shape of the species : it is a pollen grain (see: What are the morphological characteristics of pollen and spore grains?). In the majority of species, the 4 grains (resulting from the 4 microspores) split up into single grains; in some cases, they remain together (tetrad = group of 4 grains). When mature, pollen grains are released by the opening of the anthers.

A pollen grain is aimed at reaching another flower of the same species, bearing carpels. The ovaries contain ovules, in which meiosis occurs, then mitoses. It results in an embryo sac with 8 nuclei, among which an egg cell and 2 central cells. When a pollen grain arrives on another flower (see : How are the spores and pollen grains transported?), it is received by the stigmas.

The pollen grain germinates through an opening of the wall: the vegetative nucleus develops into a pollen tube which is guided by the style to the ovary, then enters the micropyle of an ovule. The pollen tube releases 2 sperm nuclei into the ovule: one of the sperms fuses with the egg cell into a zygote (2n), while the other sperm fuses with central nuclei and gives rise to albumen (= food source). There are generally several ovules in an ovary : each one can be fertilized by a distinct pollen grain.

Each fertilized ovule and its albumen form a seed that will develop into a new individual of this species. hope it works

Answer:

pollen

Explanation:

you insolent vacuum

Answer:

Il of the above are part of the Kinetic Molecular Theory

Explanation:

Answer: Which of the following are part of kinetic-molecular theory?

Choices:

1. The particles in a solid do not move.

2. The particles in a liquid are moving past one another constantly.

3. The particles in gas move freely in all directions.

4. The particles in a solid vibrate in a fixed position.

5. The particles in a solid are far apart.

6. The particles in a gas have few attractions between them.

7. The particles in all states of matter are always moving.

Explanation: Which of the following are part of kinetic-molecular theory...

Answers:

2. The particles in a liquid are moving past one another constantly.

3. The particles in gas move freely in all directions.

4. The particles in a solid vibrate in a fixed position.

6. The particles in a gas have few attractions between them.

7. The particles in all states of matter are always moving.