If each geometric shape represents a different type of atom, and atoms that are touching have chemically bonded with each other, which best describes this model? * 1. An element 2. A compound 3. A homogeneous mixture of two compounds 4. A heterogeneous mixture of two compounds 5. A homogeneous mixture of four elements 6. A heterogeneous mixture of four elements

Answer: cats r alliens because they r kind of like ufos they would usually wonder around rather u know it or not when they spy on us it could b with us sleep cooking anything so they r like aliens

Explanation:

Answer:

4HCl  +  SiO2 → 4H2O  +  SiCl4

axit clohidric  Silic dioxit  nước  Silic tetraclorua

Axit      

Explanation:

Answer:

SiCl4 + 4H2O--->Si(OH4)+4HCl

Explanation:

if you put a 4 in front of H2O it means you will have 8 hydrogens(you multiply 4 by 2) then the oxygens will be 4..on the other side that hydrogen in the brackets holds it's on 4 so that 4 isn't for both the hydrogen and the oxygen...and if you put a 4 in front of the HCl that simply means it's for both the hydrogen and oxygen.

I hope this helps

Answer:

101.87

Explanation:

that's the answer

Answer:

rise in temperature and the effect it has on our global weather patterns

Answer:

16 g

Explanation:

Step 1: Write the balanced equation

2 Na + Cl₂ ⇒ 2 NaCl

Step 2: Identify the limiting reactant

The theoretical mass ratio (TMR) of Na to Cl₂ is 46:71 = 0.65:1.

The experimental mass ratio (EMR) of Na to Cl₂ is 10:10 = 1:1.

Since EMR > TMR, Cl₂ is the limiting reactant

Step 3: Calculate the mass of NaCl produced

The theoretical mass ratio of Cl₂ to NaCl is 71:117.

10 g Cl₂ × 117 g NaCl/71 g Cl₂ = 16 g NaCl

Answer:

c

Explanation:

because mix with propanol

Answer:

a

Explanation:

because it is matter . It has change in molèculaŕ level

Answer:

Hey!

Your answer is definitely A!

Explanation:

Hope this helps!

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In an ecosystem,  the following is a consequence of urban heat islands which is  increased precipitation downwind of the city.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

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Answer:

C. the same amount of energy as

Explanation:

Firstly, a chemical reaction can either absorb energy from its surroundings to occur or release energy into its surroundings as a product. The former and latter descriptions are called ENDOTHERMIC and EXOTHERMIC reactions respectively. An exothermic reaction is that which transfers energy, in form of heat, to its surroundings while an Endothermic reaction is that which absorbs energy (heat) from its surroundings.

However, a reversible reaction is that reaction in which the formation of products from reactants and reformation of the reactants from products occur simultaneously. Hence, the products of a reversible reaction can become the reactants and move in the opposite direction. For example:

Reversible reaction: A + B ⇆ C + D means;

A + B → C + D and;

C + D → A + B

In a case whereby the opposite reactions consist of an endothermic and exothermic reactions, the endothermic reaction absorbs the same amount of energy as the exothermic reaction releases.

According to the law of conservation of energy, no energy is lost during a reversible reaction. Hence, in order to achieve an equilibrium, the amount of energy absorbed by the endothermic reaction is the same as the amount of energy released in the opposite exothermic reaction.

Answer:

Hazards Identification

Explanation:

A safety data sheet, SDS, is an informational document provided by the manufacturer or importer of a hazardous chemical detailing the chemical, physical, health, and environmental health hazards associated with the chemical as well as safety precautions in handling the chemical.

Some of the sections in the SDS include:

Product Information: It identifies the chemical as well as its recommended uses. The contact information of the manufacturer is also provided.

Fire fighting methods: It gives measures and guidelines necessary for fighting a fire caused by the chemical.

Physical and chemical properties: states the physical and chemical properties of the chemical substance such as:  appearance, odor, pH, melting/freezing point, boiling point and boiling range, flammability, etc.

Hazards identification: states the hazards of the chemical and the necessary warnings regarding the hazards. Some of the information provided include: hazard classification of the chemical (for example flammable liquid, oxidizing gases,explosives, etc), signal word, hazard statement (for example radioactive), pictograms, precautionary statements, etc.

From the above information provided, the student should refer to the hazards identification section.

Explanation:

Which is a pure substance?

1. soda

2. gasoline

3. salt water

4. carbon dioxide

carbon dioxide

Bromine, a liquid at room temperature, has a boiling point of 58°C and a melting point of -7.2°C. Bromine can be classified as a

1. compound.

2. impure substance.

3. mixture.

4. pure substance.

pure substance.

Answer:

the answer is

Explanation:

Sugar and water make a homogeneous mixture (the same proportions of its components throughout any given sample).

Answer:

The valency of calcium is +2

Explanation:

Calcium is in group two. The members of group two are divalent metals that loose two electrons to form M^2+.

Since they form M^2+, they form ionic bonds with two uninegative ions. Chlorine is in group 17. This implies that its valency is -1 and it accepts one electron when it participates in an ionic bond.

Hence it will take two chlorine atoms to receive two electrons from one calcium atom in an ionic bond making the ratio of calcium to chlorine in the compound 2:1.

Answer:

im not sure but i think its c

505 K

Answer:

Central

Explanation:

Chemistry is often called the central science because of connects the physical sciences, life sciences and applied sciences.

Chemistry is the study of matter and changes undergone by matter. This makes chemistry to occupy a central place in many scientific disciplines including medicine, engineering, pharmacy, geology etc. Basic knowledge of chemistry is usually required by experts in these disciplines.

Ionic bonds will be a metal + a nonmetal, and electrons

are transferred from the metal to the nonmetal.

A covalent bond will be a nonmetal only. Nonmetals will not give up their electrons so electrons are shared.

I have also written this on the whiteboard in the image provided.

Answer:

The correct option is;

The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles

Explanation:

The properties of the gas molecules in comparison to liquids are

1) The gas molecules are widely spread out

2) After evaporation and while in conditions favorable to the gaseous state, the kinetic energy of a gas is larger than the inter molecular attractive forces

3) A gas fills the container in which it is placed

For liquids

1) There are strong intermolecular forces holding the molecules together in a liquid

2) Liquid attractive forces in a liquid are strong enough to hold neighboring molecules

3) The volume of a liquid is definite.

Answer:

The evidence that demonstrated that the Chlorine in the stratosphere is believed to come primarily from CFCs ( Chlorofluorocarbons) rather than from natural sources such as volcanoes was due to the study conducted in which the amount of chlorine in the stratosphere over the past 20 years was measured and it was discovered that there was an increase over the years. This also corresponded with a rise in CFCs over the same period which shows that the chlorine in the stratosphere was from man made chemicals such as chlorofluorocarbons.

Chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes is evident as follows;

Discussion;

Most of the chlorine in the stratosphere is there as a result of human activities, as the figure below illustrates.

Many compounds containing chlorine are released at the ground.

Volcanoes can emit large quantities of hydrogen chloride, but this gas is rapidly converted to hydrochloric acid, which dissolves in rain water, ice, and snow and does not reach the stratosphere.

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Answer:

The volume of hydrogen gas produced at s.t.p. is 9.419 dm³

Explanation:

The balanced chemical equation for the reaction is given as follows;

Zn + 2HCl → ZnCl₂ + H₂

Therefore, we have;

One mole of Zn reacts with 2 moles of HCl to produce one mole of ZnCl₂ and one mole of H₂

Number of moles of Zn present = 25/65 = 5/13 = 0.385 moles

Therefore, number of moles of H₂ produced = 0.385 moles

The volume of hydrogen gas produced is given by the relation

PV = nRT, we have;

R = 8.3145 J/(mol·K)

V = nRT/P = 0.385 ×8.3145 ×298.15/(101325)= 0.009419 m³ = 9.419 dm³

The volume of hydrogen gas produced at s.t.p. = 9.419 dm³.

Answer:

D

Explanation:

I wish it will help you thank you

An aldehyde is a functional group that has the general formula CₓH₂ₓ₊₁CHO. The compound in option C is an aldehyde. Thus, option C is correct.

An aldehyde is a type of functional group that has a carbon atom that shares a double bond with an oxygen atom and another single bond with the R group and H group (R−CH=O).

The aldehyde functional group gives a specific chemical property to the species. The first compound is CH₃CH₂CH₂COOH is a carboxylic acid functional group. The second compound is CH₃CH₂CH₂COOCH₃ is an ester.

The third compound is CH₃CH₂CH₂CHO an aldehyde group as (R−CH=O) functional group is present. The fourth compound is CH₃CH₂CH₂COCH₃, ketone.

Therefore, option C is an aldehyde.

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Due to drought, the production of corn decreases and shortage of it occurs.

Yes, commodities in one sector should be used  in another sector because scientist invented methods in which one commodity is used in several sectors for the production of new products.

Corn was used for the production of ethanol which causes the shortage of corn that was available to consumers during and  after the drought condition of 2012 so we can conclude that due to drought, the production of corn decreases and shortage of it occurs.

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Answer:

can you type question properly.

Answer:

Yes, it is possible. Let us consider an example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.  

It is found that solution A is having more concentration in comparison to solution B in terms of mass percent. The formula for mass percent is,  

% by mass = mass of solute/mass of solution * 100

Now the formula for molality is,  

Molality = weight of solute/molecular weight of solute * 1000/ weight of solvent in grams

Now molality of solution A is,  

m = 20/121 * 1000/80 (molecular weight of RbCl is 121 grams per mole)

m = 2.07

Now the molality of solution B is,  

m = 15/58.5 * 1000/85

m = 3.02

Therefore, in terms of molality, the solution B is having greater concentration (3.02) in comparison to solution A (2.07).

Answer:

B. Cutting the supplies of oxygen

Answer:

337.5kPa ~ 338kPa

Explanation:

Using the ideal gas law PV=nRT we have the following definitions from the problem:

V(initial) = 20cm³

P(initial) = ?kPa

V(final) = 75cm³

P(final) = 90kPa

Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:

P(initial)V(initial) = nRT =P(final)V(final) ~  P(initial)V(initial) = P(final)V(final)

Rearranging this equation as we are solving for the initial pressure we find that:

P(initial) = (P(final)V(final))/V(initial)

P(initial) = ((90kPa)(75cm³))/20cm³

P(initial) = 337.5kPa ~ 338kPA

Explanation:

the intensity of a He-Ne laser (633 nm ,5 mW) transmitted by different Gase samples is observed to change in correlation with the Nd-yttrium-aluminium-garnet laser pulse (532 nm, 7.8ns ,3mJ) which excites them

Answer:

option a and c both are correct

Explanation:

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The pairs of compounds have the same empirical formula are:

a. acetylene, C₂H₂, and benzene, C₆H₆ and

c .nitrogen dioxide, NO₂, and di nitrogen tetroxide, N₂O₄

The empirical formula of a compound is defined as the formula that shows the ratio of elements present in the compound, but not the actual numbers of atoms found in the molecule.

In some cases, the empirical formula is the same as the molecular formula, which gives the actual number of atoms in a compound (e.g., H₂O).Otherwise, the molecular formula is a multiple of the empirical formula (e.g., CH₂O is the empirical formula for glucose, C₆H₁₂O₆).

Examples of empirical formulas:

Glucose has a molecular formula of C₆H₁₂O₆. It contains 2 moles of hydrogen for every mole of carbon and oxygen. The empirical formula for glucose is CH₂O.

The molecular formula of ribose is C₅H₁₀O₅, which can be reduced to the empirical formula CH₂O.

The pair with empirical formula is  acetylene, C₂H₂, and benzene, C₆H₆ and

nitrogen dioxide, NO₂, and di nitrogen tetroxide, N₂O₄

Thus, option (A) and (C) are correct.

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Answer:

C. ion concentrations are no longer changing and the voltage is 0.

Explanation:

Electrochemical cells are a device that generates current from redox reactions. In the cell, the equilibrium is reached when the voltage drops to 0. Thus, option C is correct.

An electrochemical cell is a voltaic device that uses chemical energy to generate electrical energy and vice versa. It is of two types electrolytic and galvanic cells depending on the energy it produces.

The electrochemical cell comprises two electrodes namely an anode and cathode, a salt bridge or the porous barrier, and an external connection.

The connection shows the voltage that indicates the equilibrium. When the current flow stops and the voltage reaches zero, the electrochemical cell is said to be in equilibrium.

Therefore, no change in the ionic concentrations and zero voltage indicates equilibrium.

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Answer:

Sedimentation and decantation

Explanation:

Sedimentation and decantation: Mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.

Answer:

evaporation or destillation

Explanation:

When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.

Answer:

Below is the clarification of that same particular question.

Explanation:

For that kind of weak diprotic predictor, the standard economic statement can indeed be published as:

    ⇒  [tex]H_2In_(aq)\rightleftharpoons In^{2-} +2H^+[/tex]

Answer:

ethylpentanoate

Explanation:

Alkanoic acids react with alkanols in the presence of mineral acids to yield an ester and water. This is the organic analogue of the inorganic neutralization reaction. The reaction his commonly called esterification. It is an acid catalysed reaction.

The reaction of pentanoic acid and ethanol in the presence of a string acid is shown below;

CH3CH2CH2CH2COOH(aq) + CH3CH2OH(aq) ----> CH3CH2CH2CH2COOCH2CH3(aq) + H2O(l)

The name of the compound formed is ethylpentanoate.