Can somebody please help me with these ? how many moles of AI are needed to react with 6 moles of O2?

Answer:

Approximately [tex]-74.8\; \rm kJ \cdot mol^{-1}[/tex].

Explanation:

Number the three reactions with known enthalpy changes:

[tex]\begin{aligned}& {\rm C\; (s) + O_2\; (g) \to CO_2\; (g)} & \quad \Delta H = -393.5\; \rm kJ\cdot mol^{-1}& \quad (1) \\ & {\rm H_2\; (2) + \frac{1}{2} O_2\; (g) \to H_2O\; (l)} & \quad \Delta H = -285.8\; \rm kJ\cdot mol^{-1} & \quad (2) \\ & {\rm CH_4\; (g) + 2\; O_2\; (g) \to CO_2\; (g) + 2\; H_2O\; (l)} & \quad \Delta H = -890.3\; \rm kJ\cdot mol^{-1} & \quad (3)\end{aligned}[/tex].

The goal is to find a way to combine these three reactions to obtain: [tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].

Assume that the three known reactions are combined in this way:

[tex]a \times (1) + b \times (2) + c \times (3)[/tex].

That corresponds to:

[tex]\begin{aligned} & a\; \mathrm{C\; (s)} + \left(a + \frac{1}{2}\, b + c\right) \; \mathrm{O_2\; (g)} + b\; \mathrm{H_2\; (g)} + c\; \mathrm{CH_4\; (g)} \\ & \to (a + c)\; \mathrm{CO_2\; (g)} + (b+ 2\,c )\; \mathrm{H_2O\; (l)}\end{aligned}[/tex].

Compare the coefficients of this reaction with that of the desired reaction:

[tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].

Note that some species (e.g., [tex]\rm CH_4\; (g)[/tex]) appeared on the wrong side of the equation. Their desired coefficient should be the opposite of their true coefficient. For example, the coefficient of [tex]\rm CH_4\; (g)[/tex] is supposed to be [tex]1[/tex]. However, because it appeared on the wrong side of the equation, its desired coefficient would be [tex]-1[/tex].

The coefficients of species that are not in the desired equation should be zero.

[tex]\begin{array}{|c|c|c|}\cline{1-3}\text{Species} & \text{Coefficient}& \text{Desired Coefficient} \\ \cline{1-3} \mathrm{C\; (s)}} & a & 1 \\ \cline{1-3} \mathrm{O_2\; (g)} & a + (1/2)\, b + c & 0 \\ \cline{1-3} \mathrm{H_2\; (g)} & b & 2 \\ \cline{1-3}\mathrm{CH_4\; (g)} & c & -1\\ \cline{1-3} \mathrm{CO_2\; (g)} & a + c & 0 \\ \cline{1-3} \mathrm{H_2O\; (l)} & b + 2\, c & 0\\ \cline{1-3}\end{array}[/tex].

Solve for [tex]a[/tex], [tex]b[/tex], and [tex]c[/tex]:

In other words, the desired equation is equal to [tex]1 \times (1) + 2 \times (2) - 1 \times (3)[/tex].

By Hess's Law, the enthalpy of the desired equation will be:

[tex]\begin{aligned}& 1\times \Delta H (1) + 2 \times \Delta H (2) - 1\times \Delta H(3) \\ &\approx -393.5 + 2 * (-285.8) - (-890.3) \\ &= -74.8\; \rm kJ \cdot mol^{-1} \end{aligned}[/tex].

Answer:

Greenhouse gases such as carbon dioxide and water vapor make an atmosphere around the earth and make less heat escape

Explanation:

Answer:

all of them except number 2

Explanation:

Answer:

1,3,4,5  the other perosn is correct

Explanation: That what my quiz said

Answer:

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}Y[/tex]

Explanation:

The unbalanced nuclear equation is

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e \, + \, ?[/tex]

Let's write the question mark as a nuclear symbol.

[tex]\rm _{38}^{91}Se} \longrightarrow \, _{-1}^{0}e \, + \, _{Z}^{A}X[/tex]

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.  

Then

98 =  0 + A, so A =  98 -  0 = 98, and

38 = -1 + Z, so Z  = 38 + 1 = 39

Then, your nuclear equation becomes

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}X[/tex]

Element 39 is yttrium, so the balanced nuclear equation is

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}Y[/tex]

Answer: Pounds per Cubic inch(lb/in3)

Answer:

The equilibrium concentration of gas A is 1.43 M

Explanation:

Here we have the reaction expressed as follows;

A + B → C + D and

The formula for equilibrium constant is therefore presented as follows;

[tex]K = \frac{[C]\times [D]}{[A]\times [B]}[/tex]

Where:

[C] = [D] = 2.3 M

[A] = [B]

K = 2.6

Hence, we have;

[tex]2.6 = \frac{2.3\times 2.3}{[A]\times [A]} = \frac{5.29}{[A]^2}[/tex]

[tex][A]^2= \frac{5.29}{2.6} = 2.03[/tex]

[A] = 1.43 M

The equilibrium concentration of gas A = 1.43 M.

Answer:

The equilibrium concentration of gas A = 1.43 M

Explanation:

First set up the equilibrium expression:

[tex]K = \frac{[C]\times [D]}{[A]\times [B]}[/tex]

The problem states that each product has a concentration of 2.3M at equilibrium, and that k=2.6

We also know that [A] and [B] are the same.

Since we are solving for [A] I'm going to change [A][B] to A²

[tex]2.6 =\frac{2.3^2}{A^2}[/tex]

Now we just need to solve for A²

A² = 5.29 / 2.6

A² = 2.0346

A = √2.0346

A = 1.43

Therefore, the equilibrium concentration of gas A = 1.43 M.

Answer:

The answer is NaOH

Explanation:

Strong bases are characterized by the fact that they dissociate completely in an aqueous solution. In this case, sodium hydroxide, NaOH, is classified as a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Also, it is strong because it totally breaks in its ion. And the base which breaks totally in its atom called the strong base and which doesn't it that is a weak base.

Answer:

NaOH

Explanation:

Got it right in the test. Please mark as brainliest

Answer:

C:

Explanation:

Current flows from negative to positive.So the electrons will be moving left.

when a current is applied, positive charged copper ions (called cations) leave the anode (positive electrode) and move to the cathode (negative electrode).

Answer:

coal is made from compressed plant matter and how exactly did plants grow on the surface of an ocean. (as there is no land mass beneath the arctic.)

Explanation:

it would be like finding a fly in an ice cube to simplify it.

They were surprised to find coal in arctic because ordinarily coal was supposed to be found in warm or hot environments and not cold region like the arctic.

The arctic is located at the far northern part of the world which is characterized by its extreme cold weather.

A limited vegetation of plants such as grasses, mosses and lichens are found in this region irrespective of the extreme cold weather through out the year.

Coal is a type of fuel gotten from fossils and deposits of plant vegetation.

Scientist has discovered that continents do move over time through a process called continental drift. This is the reason why limited vegetaion is found in the arctic leading to the formation of coal.

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Answer:

1.84 atm

Explanation:

P2=V1P1/V2

Temp is irrelevant because it is constant, so all you have to do is rearrange the ideal gas law.

You can check this by knowing P and V at constant T have an inverse relationship and therefore makes this the correct answer.

- Hope that helps! Please let me know if you need further explanation.

Answer:

CaC2 + 2H2O > C2H2 + Ca(OH)2

Explanation:

Count the amounts of Ca, C, H, and O, all separately on both sides.

Ca: 1                     Ca: 1

C: 2                      C:2

H: 2                      H: 4

O: 1                       O: 2

Now, your goal is to get both sides equal to each other by adding a 2 in front of H2O.

Winds are always named from the direction it blows from

Uneven heating of Earth's surface,in turn,causes differences in air pressure at various locations. Heated air rises,creating an area of low pressure beneath. Cooler air descends, creating an area of high pressure

Answer:

0.479 M or mol/L

Explanation:

So Molarity is moles/litres of solution...often written as M=mol/L

So here we are given grams of BaCl2 which we have to convert to moles. To convert to moles of BaCl2 we have to divide 63.2 g BaCl2 by molar mass of BaCl2 which is 208.23 g/mol so you get 63.2/208.23 = 0.3035 moles of BaCl2

Second step is converting the 634mL to litres by simply dividing by 1000 because we know 1 litre has 1000ml so 634/1000 = 0.634L

Now we just plug these guys in our molarity formula M=mol/L

M= 0.3035/0.634 = 0.479 M or mol/L

Answer:

Interestingly enough, I'm not getting

0.0341% w/v

either. Here's why.

Start by calculating the percent composition of chlorine,

Cl

, in calcium chloride, This will help you calculate the mass of chloride anions,

Cl

−

, present in your sample.

To do that, use the molar mass of calcium chloride, the molar mass of elemental chlorine, and the fact that

1

mole of calcium chloride contains

2

moles of chlorine atoms.

2

×

35.453

g mol

−

1

110.98

g mol

−

1

⋅

100

%

=

63.89% Cl

This means that for every

100 g

of calcium chloride, you get

63.89 g

of chlorine.

As you know, the mass of an ion is approximately equal to the mass of the neutral atom, so you can say that for every

100 g

of calcium chloride, you get

63.89 g

of chloride anions,

Cl

−

.

This implies that your sample contains

0.543

g CaCl

2

⋅

63.89 g Cl

−

100

g CaCl

2

=

0.3469 g Cl

−

Now, in order to find the mass by volume percent concentration of chloride anions in the resulting solution, you must determine the mass of chloride anions present in

100 mL

of this solution.

Since you know that

500 mL

of solution contain

0.3469 g

of chloride anions, you can say that

100 mL

of solution will contain

100

mL solution

⋅

0.3469 g Cl

−

500

mL solution

=

0.06938 g Cl

−

Therefore, you can say that the mass by volume percent concentration of chloride anions will be

% m/v = 0.069% Cl

−

−−−−−−−−−−−−−−−−−−−

I'll leave the answer rounded to two sig figs, but keep in mind that you have one significant figure for the volume of the solution.

.

Explanation:

Answer:

B. Watermelon

Explanation:

Watermelon is the only option with a definite shape that wouldn't change if you put it in a bowl

Answer:

No.4 is B No.5 is d

Explanation:

Answer:

Q 4: d

Explanation: this is all I can answer

Answer:

D. Wind Speed

Explanation:

When the question brings up 35 m/h, the m/h stands for Miles per Hour. What option can you measure the miles per hour. Here's a hint, it applies to cars as well when cops give your parents speeding tickets. Miles per Hour = Speed. So, you are measuring the wind speed.

Answer:

1 quart of lemonade will be in the first cup

Explanation:

1/4th of a gallon is a quart

Answer:

As the temperature of a sample of gas falls from 45.0ºC to 30.0ºC, its pressure falls to 300.

Explanation:

C. The concentrations of liquid water and water vapor are stable. it describes the fact that liquid water and water vapor are at equilibrium.

Hence, option (c) is correct. The concentration of liquid water and water vapor will become stable.

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Answer:

D. using a solid with a high surface area in the reactants, is your correct answer.

Explanation:

Using a solid with a high surface area in the reactants is usually associated with a higher reaction rate.

The molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a final solution volume of 500 ml is 1 M.

Molarity of a given solution is known as the total number of moles of solute per litre of the solution.  A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution.

Molarity = (No. of moles of solute ÷ Volume of solution in liters)

The unit of molarity is mol L⁻¹.

Molarity is temperature dependent because as temperature changes, volume of the solution also changes.

Given, Mass of KCl = 37.3 g

Molar mass of KCl = 74.5 g/mol

Volume of solution = 500ml = 0.5 L

No. of moles = Mass / Molar mass = 0.5

Molarity = 0.5/0.5 = 1 M

Therefore, The molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a final solution volume of 500 ml is 1 M.

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Answer:

The correct answer is The pressure of the gas will increase

The volume of the gas will increase

Explanation:

Step 1: Data given

The gas in a container is heated, this means the temperature increases

Suppose we start with a temperature of 100 K and a pressure of 1 atm and a volume of 1L

Step 2:

V1/T1= V2/T2

⇒V1 = the initial  volume = 1L

⇒T1 = the initial temperature = 100 K

⇒V2 = the new volume = TO BE DETERMINED

⇒T2 = the increased temperature = 200 K

1/100 = V2 / 200

V2 = 2 L

This means when the temperature increases, the volume will increase

P1/T1 = P2/T2

⇒P1 = the initial pressure = 1 atm

⇒T1 = the initial temperature = 100 K

⇒P2 = the new pressure = TO BE DETERMINED

⇒T2 = the increased temperature = 200 K

1/100 = P2 / 200

P2 = 2 atm

This means when the temperature increases, the pressure will increase

The correct answer is The pressure of the gas will increase

The volume of the gas will increase

Answer:

Explanation:

Hb(CO)4(aq) + 4O2(g)  ⇄  Hb(O2)4(aq) + 4CO(g)

1 )  If we increase the concentration of CO(g) , the reaction above will proceed in reverse direction to decrease its concentration,  according to Le Chatelier principle. Hence more of Hb(CO)4(aq) will be formed.

2 )  If we decrease the concentration of O₂ , then also , reaction will proceed in reverse direction . Hence concentration of Hb(CO)4(aq) will be increased .

Answer:

The planets themselves are composed of several trillions or quadrillions or more atoms. As far as hard science is concerned, it would be really hard to picture them as electrons. Conclusion: It can be said with a great accuracy that our planets are NOT huge electrons.

Rutherford's experiments showed that the mass of atoms was mostly concentrated in a very small region, with charge equal to the atomic number- the nucleus. He absolutely did not show, nor is it true, that electrons orbit the nucleus as if they were planets. That was a guess people made in trying to figure out how to picture the atom.

(Hope this helps) Sky

Answer:

sediment, metamorphic rock, sedimentary rock, weathering and erosion

Explanation:

for edge 2020

hope this helps

HAVE A GREAT DAY : )

Sediment, sedimentary rock, or metamorphic rock are the parts of the rock cycle. Therefore, the correct option is option A.

Sedimentary rocks are created by the aggregation or deposition of organic or mineral particles at the Earth's surface, following by cementation. Sedimentation refers to the mechanisms that lead these grains to settle in situ.

Any of a family of rocks formed by the modification of pre - existing rocks in reaction to changing environmental circumstances, such as temperature, pressure, or mechanical stress, as well as the addition or deletion of chemical components is  metamorphic rock. Sediment, sedimentary rock, or metamorphic rock are the parts of the rock cycle.

Therefore, the correct option is option A.

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Answer:

D working alone

Explanation:

Working alone is the only option that could potentially be a safety hazard; if you have no one watching your back, errors could occur, like dropping glass or burning your hand, and no one is around to help you.

Choices A, B, and C are not correct because those are all good safety standards.

Answer:

The temperature of the cold water is lower than the warm one. So, when we put the hand in the warm from the cold water, our hand will absorb heat, causing the hand to feel hot. Thus, we can conclude that the more heat it absorbs, the more hotter it is. Whereas the more heat it releases, the colder it is.

Answer:

Option C

Explanation:

Dipole moment being ac vector quantity has both magnitude and direction. All bonding forces have dipole moment ranging from partially positive to negative moment.  

Net dipole moment is the dipole moment arising after summation of all the existing dipole moments. On the basis of dipole moment it is determined whether the molecule is polar or non polar.  

Hence, option c is correct

Answer:c

Explanation:

Answer:

M=0.02

Explanation:

85 g NaNO3  -> 1 mol NaNO3

0.45 g NaNO3 ->x

x=(0.45 g NaNO3 * 1 mol NaNO3)/85 g NaNO3       x= 5.3 x 10^-3 mol

265 mL= 0.265 L

M= mol solute/ L solution

M= 5.3 x 10^-3 mol NaNO3/0.265 L            M=0.02