A solution of dextrose contains 25.0 g solute in 250.0 g water. How should the percentage by mass of dextrose in this solution be calculated?

Answer:

d

Explanation:

d

The answer will be - 1.67 x [tex]10^{-6[/tex]

The problem can be solved by using the rule of BODMAS.

21-4/1002-730+83920/839

First, the operation is divided into 3 parts

For the first part:

    21 - 4 = 17

For the second part:

1002-730+83920

According to BODMAS, addition operations come before subtractions.

So, the operation becomes (1002)-(730+83920)

  = (1002) - (84650)  

     = -83648

The entire operation becomes 17/-83648/839

      17/-83648 x 1/839 = -17/70180672

                                  = - 1.67 x [tex]10^{-6[/tex]

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Answer: 1

Explanation: Lithium has a single electron in the second principal energy level, and so we say that lithium has one valence electron.

1 is correct

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The Structure of polypropylene(C3H6)n is linear.

The process in which atom or small molecules joined together repeatedly to form a polymer with complex structure is called as polymerization.

The repeated unit of atom or small molecule is called monomer

Polypropylene is synthesized from the polymerization of propylene which is the monomer unit.

It has a linear structure made of propylene hydrocarbon units.

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[tex] {\qquad\qquad\huge\underline{{\sf Answer}}} [/tex]

Here we go ~

Energy difference btween the two electronic states can be expressed as :

[tex]{ \qquad \sf  \dashrightarrow \: \Delta E = h\nu} [/tex]

[ h = planks constant,[tex]{\: \nu } [/tex]= frequency ]

[tex] \qquad \sf  \dashrightarrow \:214.68 = 39.79 \times 10 {}^{ - 14} \times \nu[/tex]

[tex]\qquad \sf  \dashrightarrow \: \nu = \cfrac{214.68}{39.79 \times 10 {}^{ - 4} } [/tex]

[tex]\qquad \sf  \dashrightarrow \: \nu = \cfrac{214.68}{39.79 } \times 10 {}^{14} [/tex]

[tex]\qquad \sf  \dashrightarrow \: \nu \approx 5.395 \times10 {}^{14} \:\:hertz[/tex]

Answer:

17.3 g Cr

Explanation:

To find the mass of chromium, you need to (1) convert moles Si to moles Cr (using the mole-to-mole ratio from equation coefficients) and then (2) convert moles Cr to grams Cr (using the atomic mass). It is important to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value (0.250).

3 Si + 2 Cr₂O₃ ---> 4 Cr + 3 SiO₂
^                              ^

Atomic Mass (Cr): 51.996 g/mol

0.250 moles Si           4 moles Cr            51.996 g
-------------------------  x  --------------------  x  -------------------  =  17.3 g Cr
                                     3 moles Si              1 mole

Answer:

2.64 M

Explanation:

To find the molarity, you need to (1) convert grams to moles (via molar mass), then (2) convert mL to L, and then (3) calculate the molarity (via molarity ratio). The final answer should have 3 sig figs to match the sigs figs of the given values.

(Step 1)

Molar Mass (NH₄NO₃): 2(14.007 g/mol) + 4(1.008 g/mol) + 3(15.998 g/mol)

Molar Mass (NH₄NO₃): 80.04 g/mol

66.5 grams NH₄NO₃                1 mole
---------------------------------  x  ----------------------  =  0.831 moles NH₄NO₃
                                             80.04 grams

(Step 2)

1,000 mL = 1 L

 315 mL                1 L
--------------  x  ------------------  =  0.315 L
                        1,000 mL

(Step 3)

Molarity = moles / volume

Molarity = 0.831 moles / 0.315 L

Molarity = 2.64 M

Answer:

[OH⁻] = 2.2 x 10⁻¹²

Explanation:

(Step 1)

Calculate the pH.

pH = -log[H⁺]

pH = -log[4.6 x 10⁻³]

pH = 2.34

(Step 2)

Find the pOH.

pH + pOH = 14

2.34 + pOH = 14

pOH = 11.66

(Step 3)

Calculate the [OH⁻].

[OH⁻] = 10^(-pOH)

[OH-] = 10^(-11.66)

[OH⁻] = 2.2 x 10⁻¹²

Answer:

In the formula, we can see that for each unit of copper(II) sulfate, there are five molecules of water associated with it. One way to determine the amount of water of crystallization in a hydrated salt is to use volatilization gravimetry

Quick boiling of water can be related to the hot weather because in high temperature water changes from liquid state to gaseous state.

Water boils quickly when the weather is hot and warm because hot weather has high temperature which leads to the quick evaporation of the water. In hot weather, the liquid water changes into vapor state very quickly as compared to cold temperature.

So we can conclude that Quick boiling of water can be related to the hot weather because in high temperature water changes from liquid state to gaseous state.

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Answer:

n2(g)+3h2(g)→2nh3(g) balanced

Explanation:

Wayne Breslyn

Answer:

NH4

Explanation:

its an acid duhhhhhhhhh

Answer:

Correct answer is option C

70.0 g HNO3 and 30.0 g water

The equilibrium constant for this reaction at 350°C is determined as 5.85.

concentration of bromine, C(Br) = 0.6 mol/1 = 0.6

concentration of iodine, C(I) = 1.6 mol/1 = 1.6

An ICE table is a tabular system of keeping track of changing concentrations in an equilibrium reaction.

ICE is an abbreviation that stands for initial, change, equilibrium.

Create ICE table for the reactants and products formed;

      Br2(g)   +     I2(g)    ↔     2IBr(g)

I     0.6              1.6                 0

C    -1.19            -1.19               1.19

E    0.6 - 1.19      1.6  - 1.19       1.19

E = -0.59           0.41                1.19

The equilibrium constant is calculated as follows;

KC = [IBr]²/[Br][I]

KC = (1.19²) / (0.59 x 0.41)

KC = 5.85

Thus, the equilibrium constant for this reaction at 350°C is determined as 5.85.

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A. The heat is needed to melt 100.0 grams of ice that is already at 0°C is +33,400 J.

Specific heat capacity is the quantity of heat needed to raise the temperature per unit mass.

The heat is needed to melt 100.0 grams of ice that is already at 0°C is calculated as follows;

Q = mL

where;

Q = 100 x 334

Q = 33,400 J

Thus, the heat is needed to melt 100.0 grams of ice that is already at 0°C is +33,400 J.

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Taking into account the Henry's Law, 1.297 g carbon dioxide will dissolve at 790 mm Hg in 1.01 L water.

A change in pressure does not appreciably influence the solubility of solids or liquids or liquids in liquids; however, that of gases in solvents increases when the partial pressure of the gases increases. The solubility of a gas depends on pressure and temperature.

In this way, Henry's Law describes the effect of pressure on the solubility of gases. This law states that the solubility of a gas in contact with the surface of a liquid at a given temperature is directly proportional to the partial pressure of said gas on the liquid.

Mathematically, Henry's law is expressed as:

C=k×P

Where:

At 2 different partial pressure values, the Henry's law is expressed as:

[tex]\frac{C1}{C2} =\frac{P1}{P2}[/tex]

In this case, you know:

Replacing in Henry's Law:

[tex]\frac{1.228\frac{g}{L} }{C2} =\frac{755 mmHg}{790mmHg}[/tex]

Solving:

[tex]1.228\frac{g}{L} =\frac{755 mmHg}{790mmHg}xC2[/tex]

C2= [tex]\frac{1.228\frac{g}{L} }{\frac{755 mmHg}{790mmHg}}[/tex]

C2= 1.285 [tex]\frac{g}{L}[/tex]

Then, the concentration of carbon dioxide at 790 mmHg is 1.285 g/L. But you have 1.01 L of water. So the amount of gas dissolved can be calculated as 1.01 L×1.285 g/L = 1.297 g

Finally, 1.297 g carbon dioxide will dissolve at 790 mm Hg in 1.01 L water.

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A. The wavelength of light that is emitted is 122 nm.

Wavelength is the distance between identical points (adjacent crests) in the adjacent cycles of a waveform signal propagated in space or along a wire.

When an electron falls from the n = 2 to the n = 1 energy levels in a Hydrogen atom, the wavelength of light is emitted is calculated as follows;

¹/λ = R(1/n₁²  -  1/n₂²)

¹/λ = 109677(1/1 - 1/2²)

¹/λ = 109677(1 - ¹/₄)

¹/λ = 82,257.25

λ = 1/8,225.25

λ = 1.22 x 10⁻⁵ cm

λ = 1.22 x 10⁻⁷ m

λ = 122  nm

Thus, the wavelength of light that is emitted is 122 nm.

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Answer:

402 kJ

Explanation:

Because the energy of the reaction is positive, the reaction is endothermic. This means energy is a reactant.

You can determine how much energy/heat is absorbed using the balanced chemical equation. You can convert the moles A using the ratio composed of the coefficient in front of A and the energy required for each reaction.

2A + B + 309 kJ ⇌ 2C + 2D

2.60 moles A             309 kJ
----------------------  x  --------------------  = 402 kJ
                                 2 moles A

B. At the equivalence point of a titration of the [H+] concentration is equal to 7.

The equivalence point of a titration is a point in titration at which the amount of titrant added is just enough to completely neutralize the analyte solution.

At the equivalence point in an acid-base titration, moles of base equals moles of acid and the solution only contains salt and water.

At the equivalence point, equal amounts of H+ and OH- ions combines as shown below;

H⁺ + OH⁻  → H₂O

The pH of resulting solution is 7.0 (neutral).

Thus, the pH at the equivalence point for this titration will always be 7.0.

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From the stoichiometry of the reaction, the volume of the steam produced is 82.9 L

The term combustion is the term that is used to describe the kind of reaction that occurs when a substance is being burnt in oxygen. It is an oxidation reaction and the octane is burnt to produce carbon dioxide and steam.

We can try to write down the equation of the reaction as follows;

2C8H18(g) + 25O2(g) ------> 16CO2(g) + 18H2O(g)

Now 1 mole of octane gas occupies 22.4 L

x moles of octane gas occupies 9.1 L

x = 9.1 L  *  1 mole /22.4 L

x = 0.41 moles

Now;

2 mole of octane gas produces 18 moles of steam

0.41 moles of octane gas produces  0.41 moles  * 18 moles/2 mole

= 3.7 moles

1 mole of steam occupies 22.4 L

3.7 moles of steam occupies 3.7 moles *  22.4 L/1 mole

= 82.9 L

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The amount of heat transferred from an object depends on the following;

The initial temperature of the object

The specific heat of the object

The mass of the object

Therefore, the answer is all of the above (option B).

What is heat?

Heat is the internal energy of a system in thermodynamic equilibrium due to its temperature.

The amount of heat absorbed or released by an object can be calculated using the following expression:

Q = m × c × ∆T

Where;

Q = quantity of heat

m = mass of object

c = specific heat capacity of object

∆T = change in temperature

Therefore, this suggests that amount of heat transferred from an object depends on the following;

The initial temperature of the object

The specific heat of the object

The mass of the object

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The gases have no definite shape, low density, and are highly compressible while the liquids only have a definite volume but no definite shape.

Any substance which has mass and occupies space is called matter. Commonly, there are three states of matter that are:

There are other two states of matter that are Plasma and man-made Bose-Einstein condensates. They are not so common.

Plasma is commonly found in the universe. Stars are the superheated balls of the plasma.

Thus, gases have no definite shape, low density, and are highly compressible. On the other hand, the liquids only have a definite volume but no definite shape.

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The equilibrium constant of the reaction is 76176.

In chemistry, the equilibrium constant is used to show the extent to which we can convert reactants to products in a given chemical process. A large value of the equilibrium constant shows that most of the reactants are converted into products under the given conditions. A small value of the equilibrium constant shows that most of the reactants are not converted into products.

Thus, if we have the reactions;

(1) 1/2 X2(g) + 1/2 Y2(g) ↔ XY(g)

(2) 2XY(g) ↔ X2(g) + Y2(g)

It then follows that;

K1 = [XY]/[X2]^1/2 [Y2]^1/2

K2 =  [XY]^2/[X2] [Y2]

It is clear that;

K2 = (K1)^2

K2 = (276)^2

K2 = 76176

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Answer: Lithium - 8

Answer:

Lithium-8

Explanation:

The atom with three protons and five neutrons that has a mass number of eight is known as lithium-8.

Answer:

The answer is The unsorted sand and rock is the least porous.

Answer:

large pebbles and boulders

Answer:

The correct answer is A

Explanation:

Ionic compounds conduct electricity when molten (liquid) or in an aqueous solution because their ions are free to move from place to place

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Answer:

131 atm

Explanation:

To find the new pressure, you need to use Boyle's Law:

P₁V₁ = P₂V₂

In this equation, "P₁" and "V₁" represent the initial pressure and volume. "P₂" and "V₂" represent the final pressure and volume. You can find the new pressure (P₂) by plugging the given values into equation and simplifying.

P₁ = 3.88 atm                       P₂ = ? atm

V₁ = 7.74 L                           V₂ = 0.23 L

P₁V₁ = P₂V₂                                                      <----- Boyle's Law

(3.88 atm)(7.74 L) = P₂(0.23 L)                       <----- Insert values

30.0312 = P₂(0.23 L)                                      <----- Simplify left side

131 = P₂                                                          <----- Divide both sides by 0.23

Answer:

The balanced equation is 5Fe2++MnO-4+8H+→5Fe3++Mn2++4H2O .

Explanation:

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Answer:

5Fe2++MnO-4+8H+→5Fe3++Mn2++4H2O .

Explanation: