Which of the following observations about burning sugar provides evidence of a
chemical reaction?
a. Heat is added to the sugar crystals.
b. The sugar melts and becomes a liquid.
с
C. The temperature of the sugar increases.
d. Gas is produced as the sugar turns black.
1 Pt
А
B
D

Answer:

There are 54.03 grams in 3 moles of H2O

There are 3.2 moles in 519.3 g FeCl3

There are 56.0 g in 2 moles of CO

Explanation:

H2O molar mass: 18.01 g/mol

   to calculate the grams:  3 mol H2O * 18.01 g/mol

FeCl3 molar mass: 162.2 g/mol

   to calculate moles:  519.3g FeCl3 / 162.2 g/mol

CO molar mass: 28.01 g/mol

   to calculate grams: 28.01 g/mol CO * 2 mol CO

Answer:

d

Explanation:

The material that represents the crust is option d. Thin layer of plaster.

It is the outermost shell of a planet i.e. terrestrial.  The crust of the earth should be split into older, thicker continental crust, etc. Also, it is made of solid rocks and minerals. Due to this, the thin plaster layer represents the material for the crust.

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Answer:

Melting: the substance changes back from the solid to the liquid. Condensation: the substance changes from a gas to a liquid. Vaporization: the substance changes from a liquid to a gas. Sublimation: the substance changes directly from a solid to a gas without going through the liquid phase.

Explanation:

The change in appearance of a substance when it changes its phase includes :

Change in volume : when a liquid substance is heated to its boiling point ( vaporization) the volume of the liquid substance will change when it turns into gas because gases have no definite volume or shape.

Change in Texture: When water freezes it changes its state from a liquid state to a solid state, also the appearance of the liquid water will undergo changes in its texture when it is in its' solid state ( i.e. the texture of ice is not exactly the texture of liquid water )  

Change in shape : when a solid substance changes its state from solid to gas ( sublimation ) the shape of the solid substance will be lost during the phase change.

Hence we can conclude that the change in the appearance of a substance when it changes its phase include. Change in volume, Change in texture and Change in shape.    

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Answer:

CO2

Electron pair geometry- Linear

Molecular geometry- Linear

BF3

Electron pair geometry - Trigonal planar

Molecular geometry- trigonal planar

SO2

Electron geometry - Trigonal planar

Molecular geometry - bent

SiCl4

Electron geometry- tetrahedral

Molecular geometry - tetrahedral

PF3

Electron pair geometry - tetrahedral

Molecular geometry- trigonal pyramidal

OF2

Electron pair geometry- tetrahedral

Molecular geometry- bent

Explanation:

Considering the molecule CO2, there are two regions of electron density in the molecule positioned at an angle of 180 degrees from each other hence the molecule is linear.

For BF3, the three bond pairs are arranged at the corners of a triangle to give a trigonal planar geometry at a bond angle of 120 degrees.

SO2 has two bonding groups and one lone pair giving three regions of electron density and a trigonal planar electron pair geometry. Due to the distortion to geometry caused by the presence of a lone pair, the molecule is bent.

For SiCl4, the four bonding groups are arranged at the corners of a regular tetrahedron hence it is tetrahedral both in electron pair geometry and in molecular geometry.

PF3 molecule has four regions of electron density corresponding to tetrahedral electron pair geometry. The presence of the lone pair leads to a trigonal pyramidal molecular geometry.

For OF2, there are four regions of electron density around the central oxygen atom. Two bond pairs and two lone pairs leads to a tetrahedral electron pair geometry but a bent molecular geometry is observed due to the two lone pairs.

Answer:

Concave Lenses Are for the Nearsighted, Convex for the Farsighted. Concave lenses are used in eyeglasses that correct nearsightedness.

Explanation:

Answer:

See explanation

Explanation:

Let us have it behind our minds that the dielectric constant reveals the degree of polarity of a molecule. This implies that the more polar a molecule is, the greater its dielectric constant.

Chloroform is a polar molecule while carbon tetrachloride is a nonpolar molecule due to its symmetrical nature. Thus Chloroform has  a greater degree of polarity and consequently a higher dielectric constant.

Methanol is more polar than ethanol because polarity of the molecule decreases as more CH2s are added to the molecule, that is, polarity of the molecule decreases with increase in the length of the carbon chain. Since methanol is more polar than ethanol, it should have a greater dielectric constant.

Again, the presence of more akyl groups in acetone makes it less polar than formamide. Consequently, formamide has a greater dielectric constant than acetone.

Answer:

To answer this question we would need the Molecular empirical formula that relates the reactant of N2 to the final product of CH3NH2. Then it would be easily solved by using stoichiometric ratios. Basically it is done similar to unit conversion problems.

Answer:

The ability to do work is energy.

Hope it helps!!!

Explanation:

given

kpo4 it has molar mass of 39+31+(16*4)=134

m=n*Mm

m=5.35*134

m=716.9

Answer: B. The rate goes down

Explanation:

Answer: Ca(NO3)2(aq) + 2NaOH(aq) —> Ca(OH)2(s) + 2NaNO3(aq)

Substitution

Explanation:

The given reaction is a substitution reaction in which hydroxil group is exchanged between compounds.

Substitution Reaction:

It is a reaction in which functional group of a compound replaced by the another functional group.

For example-

[tex]\bold {Ca(NO3)_2(aq) + 2NaOH(aq) \rightarrow Ca(OH)_2(s) + 2NaNO_3(aq)}[/tex]

In the reaction hydroxil group is exchanged between compounds.

1 mole of aqueous calcium nitrate react with  2 moles aqueous sodium hydroxide to produce  1 mole of solid precipitate calcium hydroxide and 2 moles aqueous sodium nitrate.

Therefore, the given reaction is a substitution reaction in which hydroxil group is exchanged between compounds.

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Answer:

5.13 g of CO₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

C₁₂H₂₂O + 17O₂ —> 12CO₂ + 11H₂O

Next, we shall determine the mass of C₁₂H₂₂O that reacted and the mass of CO₂ produced from the balanced equation. This can be obtained as follow:

Molar mass of C₁₂H₂₂O = 182 g/mol.

Mass of C₁₂H₂₂O from the balanced equation = 1 × 182 = 182 g

Molar mass of CO₂ = 12 + (2×16)

= 12 + 32

= 44 g/mol

Mass of CO₂ from the balanced equation = 12 × 44 = 528 g

SUMMARY:

From the balanced equation above,

182 g of C₁₂H₂₂O reacted to produce 528 g of CO₂.

Finally, we shall determine the mass of CO₂ produced from the reaction. This can be obtained as follow:

From the balanced equation above,

182 g of C₁₂H₂₂O reacted to produce 528 g of CO₂.

Therefore, 1.77 g of C₁₂H₂₂O will react to produce = (1.77 × 528)/182 = 5.13 g of CO₂.

Thus, 5.13 g of CO₂ were obtained from the reaction.

Answer:

Hope this helps! （；＿；)/

Explanation:

Answer:

288g

Explanation:

Given parameters:

Number of moles of H₂O  = 16moles

Unknown:

Mass of the water = ?

Solution:

To solve this problem, first find the molar mass of H₂O;

     Molar mass of H₂O = 2(1) + 16  = 18g/mol

Mass of H₂O = number of moles x molar mass

                      =  16 x 18

                      = 288g

The numbers inside the box represent the number of protons or atomic number while the circles represent the energy levels or shells in the atom. The dots represent the electrons occupying those shells.

The atomic number refers to the number of protons in the nucleus of an atom. It is shown as the number inside the boxes. It serves as the identity of an element.

The electrons occupy shells of particular energy levels according to Bohr model. The circles represent these energy levels. The dots in the circles represent the electrons that occupy those energy levels.

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Answer:

The lumps should be removed in brown sugar and to be rolled with rolling pin.

Explanation:

In preparing brown sugar as ingredients in baking and pastry, it is important to check if the sugar is lumpy. Although it is not the main ingredient in baking, it is important to check because it could affect the texture of the mixtures. Brown sugar is also much nutritious to white sugar  that is why it is more commonly use. The brown sugar become lumpy because when brown sugar is exposed to air it gets harder because the molasses that keeps its soft evaporates that makes the sugar stick together. The rolling pin helps the lump to break up.

Answer:

b. tendency for a substance to achieve maximum disorder (i.e., randomly distribute).

Explanation:

Entropy can be defined as the tendency for a substance to achieve maximum disorder (i.e., randomly distribute).

This ultimately implies that, entropy is a thermodynamic quantity that measures the degree of maximum order or randomness of a system.

The S.I unit used for the measurement of the degree of maximum order or randomness of a system is Joules per Kelvin (JK¯¹). An example of entropy is the mixing of ideal gases.

This question is incomplete, the complete question is;

A 17.0 g sample of quartz, which has a specific heat capacity of 0.730 J.g⁻¹°C⁻¹, is dropped into an insulated container containing 200.0 g of water at 85°C and a constant pressure of 1 atm . The initial temperature of the quartz is 7.2°C.  

Assuming no heat is absorbed from or by the container, or the surroundings, calculate the equilibrium temperature of the water. Be sure your answer has the correct 3 number of significant digits.  

Answer:

the equilibrium temperature of the water is 83.9°C

Explanation:

Given the data in the question;

Since no heat is absorbed from or by the container, or the surroundings;

Then  Heat lost by the quartz = heat gained by water

ΔH1 = ΔH2

DH = mcΔT

where m is mass, C is specific heat capacity and ΔT is temperature change;

so

(mcΔT)1 = (mcΔT)2

we know that; specific heat capacity of is 4200 Joule/Kilogram K (J/kg∙K) = 4.2 (J/g∙°C)

we substitute

17.0g × 0.730 J.g⁻¹°C⁻¹ × ( 7.2°C - T2)  = 200.0g × 4.2 J/g∙°C × ( T2 - 85°C)

89.352 -  12.41T2 = 840T2 - 71400

840T2 + 12.41T2 = 89.352 + 71400

852.41T2 = 71489.35

T2 = 71489.35 / 852.41 = 83.86°C ≈ 83.9°C

Therefore, the equilibrium temperature of the water is 83.9°C

Answer:

8 × 10³ mol N₂

Explanation:

Step 1: Write the balanced equation

2 C₃H₅N₃O₉ ⇒ 6 CO₂ + 5 H₂O + 0.5 O₂ + 3 N₂

Step 2: Convert the mass of C₃H₅N₃O₉ from tons to grams

We will use the conversion factor 1 t = 907185 g.

1.320 t × 907185 g/1 t = 1.197 × 10⁶ g

Step 3: Calculate the moles corresponding to 1.197 × 10⁶ g of C₃H₅N₃O₉

The molar mass of C₃H₅N₃O₉ is 227 g/mol.

1.197 × 10⁶ g × 1 mol/227 g = 5.27 × 10³ mol

Step 4: Calculate the moles of N₂ formed from 5.27 × 10³ moles of C₃H₅N₃O₉

The molar ratio of C₃H₅N₃O₉ to N₂ is 2:3.

5.27 × 10³ mol C₃H₅N₃O₉ × 3 mol N₂/2 mol C₃H₅N₃O₉ = 7.91 × 10³ mol N₂ ≈ 8 × 10³ mol N₂

Answer:

[tex]m_{NaCl}=19.9gNaCl[/tex]

Explanation:

Hello!

In this case, since the formula for the calculation of molarity is:

[tex]M=\frac{n}{V}[/tex]

Whereas we can compute the moles of the solute as shown below, making sure the volume is in liters:

[tex]n=M*V[/tex]

Thus, by plugging in we obtain:

[tex]n=0.200L*1.70mol/L=0.170molNaCl[/tex]

Next, since the molar mass of NaCl is 58.44 g/mol, we obtain the following mass:

[tex]m_{NaCl}=0.170molNaCl*\frac{58.44gNaCl}{1molNaCl}\\\\m_{NaCl}=19.9gNaCl[/tex]

Best regards!

Answer:

Replacement is your answer

Answer:

The outer shell of the new star will start to expand.

Explanation:

The new star will continue to glow for millions or even billions of years. As it glows, hydrogen is converted into helium in the core by nuclear fusion. The core starts to become unstable and it starts to contract. The outer shell of the star, which is still mostly hydrogen, starts to expand.

Explanation provided by:

StarChild: Stars - NASA

Answer:

The anwer is not D the anwer is A

Explanation:

Answer:

Explanation:

1:) A

Mostly just use context clues

2:) D

The climate on earth is mostly due to earth's atmosphere. So, no, the moon doesn't have similar weather

According to the mole concept, there are 4.54 moles present in 200 grams of carbon dioxide.

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass  in grams present in one mole  of atoms is its atomic mass.Number of mole= mass /molar mass which is 200/44=4.54 moles

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