Question 5
Complete the following analogy:
Reflection nebulae : blue :: emission nebula:
Greenish-blue
Yellow
Red
Pinkish-red

Answer:

HE

Explanation:

HE is a noble gas

Answer:

A via A P E X

The entity that would make ΔG to become negative at a given enthalpy and entropy is Changing the temperature (Option A)

ΔG = ΔH – TΔS

Where

NOTE

ΔG = +ve (non spontaneous)

ΔG = 0 (equilibrium)

ΔG = –ve (spontaneous)

From the Gibbs free energy equation, we can see that the entities that makes us the equation are

Thus, we can conclude that the correct answer to the question is: changing the temperature (Option A) since the equation has nothing to do with neither concentration, pressure nor volume

Learn more about Gibbs free energy:

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Answer:

from the chromosome..l dont know

Answer:

People are concerned with the rising level of carbon dioxide in the atmosphere because it could be leading to global warming, which is the observed increase of the Earth's temperatures. Engineers are working to rebalance the carbon cycle by designing appliances, buildings and homes that use less energy.

Explanation:

I don’t know if I’m right..........

Answer:

100 g/mol

Explanation:

The equation of the reaction;

Ca^2+(aq) + EDTA(aq) -----> (CaEDTA)^2-(aq)

Let CA = concentration of EDTA

VA = volume of EDTA

NA= number of moles of EDTA

CB= concentration of marble

VB = volume of marble

NB= number of moles of marble

CAVA/CBVB = NA/NB

CAVANB=CBVBNA

CB = CAVANB/VBNA

CB = 0.01052 *  23.56  * 1/10.00  * 1

CB = 0.02479 M

number of moles = concentration * volume

number of moles = 0.02479 M * 100.00/1000L

number of moles = 2.479 * 10^-3 moles

number of moles = mass/molar mass

molar mass =  0.2481g/2.479 * 10^-3 moles

molar mass =  100 g/mol

Answer:

There are 2.85 x 10^22 atoms of carbon in a diamond with a mass of 0.568 g.

Hope this helps! :)

Answer:

Percentage yield = 23.8%

Explanation:

We'll begin by determining the limiting reactant. This can be obtained as follow:

Xe(g) + 2F₂(g) —> XeF₄

From the balanced equation above,

1 mole of Xe reacted with 2 moles of F₂.

Therefore, 2.2 moles of Xe will react with = 2.2 × 2 = 4.4 moles of F₂.

From the above calculation, we can see that a higher amount (i.e 4.4 moles) of F₂ than what was given (i.e 2.1 moles) is needed to react completely with 2.2 moles Xe.

Therefore, F₂ is the limiting reactant and Xe is the excess reactant.

Next, we shall determine the theoretical yield of XeF₄.

This can be obtained by using the limiting reactant as follow:

From the balanced equation above,

2 moles of F₂ reacted to produce 1 mole of XeF₄.

Therefore, 2.1 moles of F₂ will react to produce = (2.1 × 1)/2 = 1.05 moles of XeF₄.

Thus, the theoretical yield of XeF₄ is 1.05 moles.

Finally, we shall determine the percentage yield. This can be obtained as follow:

Actual yield of XeF₄ = 0.25 mole

Theoretical yield of XeF₄ = 1.05 moles

Percentage yield =?

Percentage yield = Actual yield / Theoretical yield × 100

Percentage yield = 0.25 / 1.05 × 100

Percentage yield = 0.238 × 100

Percentage yield = 23.8%

Answer:

69mol

Explanation:

The balanced chemical equation given in this question is as follows;

N₂ + 3H₂ → 2NH₃

The above balanced equation shows that 3 moles of hydrogen gas (H2) reacts to produce 2 moles of ammonia (NH3).

To convert the given mass of hydrogen to moles, we use the following formula:

mole = mass/molar mass

Molar mass of H2 = 2g/mol

mole = 207/2

= 103.5mol

If 3 moles of H2 produce 2 moles of NH3,

Then, 103.5mol of H2 will produce 103.5 × 2 / 3

= 207/3

= 69mol

Answer:

d.7 is the correct answer

Answer:

ΔH = 46.2 kJ

Explanation:

Hello there!

In this case, according to the given set of reactions and the required one, it is possible to apply the Hess' rule in order to realize the following manipulations to obtain the required reaction:

1. Keep this reaction as it is.

2Fe(s) + O2(g) => 2FeO(s) ΔH = -545.6 kJ

2. Keep this reaction as it is.

4Fe(s) + 3O2(g) => 2Fe2O3(s) ΔH = -1,643.6 kJ

3. Reverse double this reaction so that we obtain:

2Fe3O4(s) => 6Fe(s) + 4O2(g) ΔH = -(-1,117.7 kJ)*2=2235.4kJ

Add them up to obtain:

2Fe(s) + O2(g) + 4Fe(s) + 3O2(g) + 2Fe3O4(s) => 6Fe(s) + 4O2(g) +2Fe2O3(s) + 2FeO(s)

Simplify common terms to obtain:

2 Fe3O4(s) => 2 Fe2O3(s) + 2 FeO(s)

Therefore, the enthalpy of such reaction is:

ΔH = 2235.4kJ -545.6 kJ -1,643.6 kJ

ΔH = 46.2 kJ

Best regards!

Answer:

C. 1000

l think this is correct answer

l hope it's helpful for you

Answer:

about 5 hours

Explanation:

When doing this problem you mmust mulitiply 4 x 74 and divide the answer by 60 because 60=1 hour.

Answer: 1. Highest osmotic pressure : 1 M [tex]MgCl_2[/tex]

2. Lowest osmotic pressure:  1 M [tex]C_{12}H_{22}O_{11}[/tex]

Explanation:

[tex]\pi=i\times C\times R\times T[/tex]

[tex]\pi[/tex]= osmotic pressure

i = Van'T Hoff factor  

C = concentration  

T = Temperature  

1. For 1M [tex]MgCl_2[/tex]  

, i= 3 as it is a electrolyte and dissociate to give 3 ions.

[tex]MgCl_2\rightarrow Mg^{2+}+2Cl^{-}[/tex]  

2. For 1 M [tex]KCl[/tex]

, i= 2 as it is a electrolyte and dissociate to give 2 ions.

[tex]KCl\rightarrow K^{+}+Cl^{-}[/tex]

3. For  1M [tex]C_{12}H_{22}O_{11}[/tex]

, i= 1 as it is a non electrolyte and do not dissociate.  

Thus as vant hoff factor is highest for [tex]MgCl_2[/tex] thus osmotic pressure is highest for 1 M [tex]MgCl_2[/tex]

And as vant hoff factor is lowest for [tex]C_{12}H_{22}O_{11}[/tex] thus osmotic pressure is lowest for  1 M [tex]C_{12}H_{22}O_{11}[/tex]

Answer:

3.30 gSiO2 / 60.085g SiO2 x 2 mol 0 / 1 mol SiO2 x (6.022*1023 ) = 6.61*1022 O atoms

Explanation:

Answer:

a. The condition that a reaction takes place without outside help Spontaneity

b. Difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature Gibbs free energy

c. Sum of the internal energy plus the product of the pressure and volume for a reaction   Enthalpy.

d. The extent of randomness in a system Entropy

e. Solution in which no more solute can be dissolved in the solven Saturated solution

Explanation:

 (a) SPONTANEITY - The quality of being natural rather than planned in advance is described as spontaneity.

(b) GIBBS FREE ENERGY - Gibbs free energy, also known as the Gibbs function, Gibbs energy, or free enthalpy, is a quantity used to quantify the maximum amount of work that can be performed in a thermodynamic system when the temperature and pressure are held constant. The symbol ‘G' stands for Gibbs free energy.

(c) ENTHALPY - The heat absorbed or released during a process at constant pressure is equal to the Enthalpy shift. While “enthalpy” is often referred to as “heat content,” most people prefer to refer to it as “enthalpy.”

(d) ENTROPY - Entropy is the amount of thermal energy in a device per unit temperature that can't be used to do useful work. Since work is produced by ordered molecular motion, entropy is also a measure of a system's molecular disorder, or randomness. For several everyday phenomena, the idea of entropy offers profound insight into the direction of spontaneous change.

(e) SATURATED SOLUTION - A saturated solution is a chemical solution that contains the maximum amount of dissolved solute in the solvent. In a saturated solution, the extra solute will not dissolve. A number of factors influence the amount of solute that can be dissolved in a solvent to form a saturated solution.                              

Answer:

B.) 14

Explanation:

27-13=14 neutrons

Answer:

3-

Explanation:

Answer:

The sample of __Ca___ contains the greatest number of atoms

Explanation:

As we know,

1 mole [tex]= 6.022*10^{23}[/tex] molecular entities (Can be atom, ions or molecules)

Number of atoms in 1.76 mole sample of Be

[tex]= 6.022*10^{23} *1.76\\= 1.059 * 10^{24}[/tex]

The sample of __Ca___ contains the greatest number of atoms

Answer:

Average atomic mass = 32.057 u

Explanation:

Average atomic mass = Σ(isotope × abundance)

Average atomic mass = (0.95 × 31.972) + (0.0076 × 32.971) + (0.0422 × 33.967)

Average atomic mass = 32.057 u

Answer:

2.41x10²¹ atoms

Explanation:

mass of nickel that are present in the coin can be determined Using ( 25% nickel) with j mass of coin= 0.942g )

mass of nickel = (0.942g) × (25/100)

= 0.2355g of Nickel

We need to convert this " gram" into " moles"

Mole= mass/ molar mass

Molar mass= 58.69 g/mol

0.2355 g) / (58.69 g/mol)

= 0.004 mol

We need to convert the moles to

number of atoms.

Avogadro's number= 6.023x10²³ atoms/mol

(0.004 × 6.023x10²³ atoms/mol)

=2.41x10²¹ atoms

Answer:

Fires --> These consume fuel and convert chemical energy stored in that fuel into thermal light and sound energy.

Decay -->The breakdown of dead plants and animals releases thermal energy.

Earth --> Thermal energy comes from deep inside and it is called geothermal energy.

Answer:

Given : Diatomic molecule at 273K

'q' absorbed = positive = +100Cal = 100 x 4.184J = 418.4J

'W' done by system = negative = -209J

By first law of thermodynamics;

ΔU = q + W = 418.4 + (-209) = 209.4J

We know for diatomic molecule Cv=25R and CvΔT=ΔU

CvΔT=209.4

 25RΔT=209.4

ΔT=5R209.4×2

And, Heat exchange=Cm×ΔT 

where; Cm is molar heat capacity

Cm=ΔTHeat Exchange

substituting values for Heat Exchange = 418.4 and ΔT=5R209.4×2

Cm=5R

Answer:

The volume of reactant measured at STP left over is 409.9 L

Explanation:

Answer:

There are 36 grams in 4.00 moles of Carbon.

Explanation:

In order to convert from moles of a substance into grams of the same substance, we need to use the substance's molar mass.

That means that in this case we use the molar mass of Carbon:

Thus, there are 36 grams in 4.00 moles of Carbon.

Shaking causes small bubbles, which helps the soda's carbon dioxide escape faster. The gas will gradually escape from the liquid as bubbles once the can is opened, and the soda will become "flat." The dissolved gas takes a long time to escape if the liquid is treated gently.