5
Select the correct answer.
Which of the following is a physical model of the Sun?
A.
an equation that describes the Sun's motion
B.
a chart that lists the temperatures of different parts of the Sun
O c.
a computer program that shows how the Sun changes over time
OD
a paragraph that describes the Sun's structure
O E.
a small yellow ball that represents the Sun
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Answer:

1. Balanced Molecular equation

Ca(OH)2(aq) + 2HCl(aq) —> CaCl2(aq) + 2H2O(aq)

2. Net ionic equation

OH-(aq) + H+(aq) —> H2O(l)

Explanation:

1. Molecular balance equation for the reaction between Ca(OH)2(aq) and HCl(aq).

This is illustrated below:

Ca(OH)2(aq) + HCl(aq) —> CaCl2(aq) + H2O(aq)

There are 2 atoms of Cl on the right side and 1 atom on the left side. It can be balance by putting 2 in front of HCl as shown below:

Ca(OH)2(aq) + 2HCl(aq) —> CaCl2(aq) + H2O(aq)

There are 2 atoms of H on the right side and a total of 4 atoms on the left side. It can be balance by putting 2 in front of H2O as shown below:

Ca(OH)2(aq) + 2HCl(aq) —> CaCl2(aq) + 2H2O(aq)

Therefore the equation above is balanced.

2. Net ionic equation for the reaction between Ca(OH)2(aq) and HCl(aq).

In solution, Ca(OH)2(aq) and HCl(aq) will dissociate as follow:

Ca(OH)2(aq) —> Ca2+(aq) + 2OH-(aq)

HCl(aq) —> H+(aq) + Cl-(aq)

Ca(OH)2(aq) + 2HCl(aq) —>

Ca2+(aq) + 2OH-(aq) + 2H+(aq) + 2Cl-(aq) —> Ca2+(aq) + 2Cl-(aq) + 2H2O(l)

Cancel out the spectator ions i.e Ca2+ and Cl- to obtain the net ionic equation

2OH-(aq) + 2H+(aq) —> 2H2O(l)

OH-(aq) + H+(aq) —> H2O(l)

Answer:

7.5 g

Explanation:

There is some info missing. I think this is the original question.

Ammonium phosphate ((NH₄)₃PO₄) is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid (H₃PO₄) with ammonia (NH₃). What mass of ammonium phosphate is produced by the reaction of 4.9 g of phosphoric acid? Be sure your answer has the correct number of significant digits.

Step 1: Write the balanced equation

H₃PO₄ + 3 NH₃ ⇒ (NH₄)₃PO₄

Step 2: Calculate the moles corresponding to 4.9 g of phosphoric acid

The molar mass of phosphoric acid is 98.00 g/mol.

[tex]4.9 g \times \frac{1mol}{98.00g} = 0.050mol[/tex]

Step 3: Calculate the moles of ammonium phosphate produced from 0.050 moles of phosphoric acid

The molar ratio of H₃PO₄ to (NH₄)₃PO₄ is 1:1. The moles of (NH₄)₃PO₄ produced are 1/1 × 0.050 mol = 0.050 mol.

Step 4: Calculate the mass corresponding to 0.050 moles of ammonium phosphate

The molar mass of ammonium phosphate is 149.09 g/mol.

[tex]0.050mol \times \frac{149.09 g}{mol} = 7.5 g[/tex]

Answer:

the total I think would be 35

Answer: The scientific method attempts to minimize the influence of bias or prejudice in the experimenter. Even the best-intentioned scientists can't escape bias. ... That's the job of the scientific method. It provides an objective, standardized approach to conducting experiments and, in doing so, improves their results.

Answer:

A. POBr will be consumed in order to establish a new equilibrium.

Explanation:

POBr3(g) =POBr(g) + Brz(g)

The question is based on Le Chatelier's principle. This principle states that whenever a system at equilibrium is stressed, the system would undergo changes to annul that stress.

If more POBr  is added to the system, it means that the concentration of the products have been increased and as a result the equilibrium has been disturbed. To restore equilibrium, the system would have to shift in a direction that reduces the product concentration.

This direction is the backward direction and in doing so, POBr will be consumed.

The correct option is option A.

The statement that describes the behavior of the system is:

A. POBr will be consumed in order to establish a new equilibrium.

POBr₃(g)  ⇄ POBr(g) + Br₂(g)

According to Le Ch-atelier principle,  if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to re-establish an equilibrium.

If more POBr is added to the system, it means that the concentration of the products have been increased and as a result the equilibrium has been disturbed. To restore equilibrium, the system would have to shift in a direction that reduces the product concentration.

This direction is the backward direction and in doing so, POBr will be consumed.

Thus, the correct option is option A.

Find more information about Equilibrium here:

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Answer:

[tex]7.5x10^{-3}M[/tex]

Explanation:

Hello,

In this case, since the dissociation barium fluoride is represented at equilibrium by:

[tex]BaF_2(s)\rightleftharpoons Ba^{2+}(aq)+2F^-(aq)[/tex]

Hence, the equilibrium expression is:

[tex]Ksp=[Ba^{2+}][F^-]^2[/tex]

Whereas the molar solubility is represented as the reaction extent [tex]x[/tex]:

[tex]Ksp=[x][2x]^2[/tex]

In such a way, we can solve for [tex]x[/tex]:

[tex]1.7x10^{-6}=4x^3\\\\x=\sqrt[3]{\frac{1.7x10^{-6}}{4} } \\\\x=7.5x10^{-3}M[/tex]

Which as said before, is the molar solubility.

Best regards.

Answer:

In solving this question it is important to note that entropy is referred to as the degree of randomness in a compound or system.

Entropy is highest in gas and lowest in solids

The order is given as:

Gas > Liquid > Solid

Another criteria is the more the elements in a compound, the more the entropy.

For example: KO3 has more entropy than KO2 due to the presence of more elements.

The last criteria is calculating their masses , the one with a greater mass has the higher entropy.

The option with the least entropy will be a solid. Al(s) and NaF(s) are both solids. NaF(s) has more elements in a compound which makes it have a higher entropy than Al(s). This means NaF(s) > Al(s).

The next to consider are the gaseous compounds which are HF(g) , SiF4(g) and SiH4(g). The least entropy will be HF(g) . This is because it has the least number of elements of the 3 compounds.

SiF4(g) and SiH4(g) have equal number of elements in a compound but the one with the highest mass is SiF4(g) because fluorine has a higher mass when compared to hydrogen. This means the compound with the highest entropy is SiF4(g).

The order of increasing entropy is given below:

Al(s) < NaF(s) < HF(g) < SiH4(g) < SiF4(g)

Answer:

2 lone pairs of electrons

Explanation:

In this case, the central atom is oxygen. If we check the periodic table we will have an atomic number of 8. So, the electronic configuration would be:

[tex]1s^2~2s^2~2p^4[/tex]

We have 6 electrons in the last level. Therefore, we have 6 valence electrons. For the hydrogens, we will have only 1 electron each. So, in total, we have 8 electrons.

With this in mind, we have to draw two lone pairs in the oxygen and 1 bond with each hydrogen.

See figure 1.

I hope it helps!

Answer:

The answer of the scientific STATEMENT is" Appears That Ants Live In Colonies."

Answer:

D) Measure 58.44g NaCl, dissolve it into 400ml water, and then top off to 500ml in a volumetric flask.

Explanation:

Step 1: Given data

Molarity (M): 2.00 M

Volume (V): 500 mL = 0.500 L

Molar mass of NaCl: 58.44 g/mol

Step 2: Calculate the required moles of NaCl

We will use the following expression.

n = M × V

n = 2.00 mol/L × 0.500 L

n = 1.00 mol

Step 3: Calculate the mass corresponding to 1.00 moles of NaCl

1.00 mol × 58.44 g/mol = 58.44 g

Step 4: Describe the procedure to prepare the solution

Measure 58.44g NaCl, dissolve it into 400ml water, and then top off to 500ml in a volumetric flask.

Answer:

D) Measure 58.44g NaCl, dissolve it into 400ml water, and then top off to 500ml in a volumetric flask.

Explanation:

I got it right in class!

Hope  this helps!! :))

Answer:

3,5-dichlorohex-1-ene

Explanation:

The compound is; H2C=CH-C(Cl)H-CH2-C(Cl)H-CH3. We can rightly call this compound by the name, 3,5-dichlorohex-1-ene.

We arrived at this name by first counting the longest parent carbon chain, that gives hexane. The compound has a double bond at the 1-position. Also, there are two substituent chlorine atoms at positions 3 and 5 in the structure, hence the name given.

Answer:

b) The boiling point of the solution is always greater than the boiling point of the pure solvent.

Explanation:

Hello,

In this case, when we add a nonvolatile solute to a volatile solvent which has a relatively low boiling point, we can evidence the increase of the boiling point of the resulting solution as more energy must be supplied to take the molecules from liquid to gas. This fact matches with the boiling point elevation colligative property due to the solute's addition, which states that the boiling point of the solution is always greater than the boiling point of the pure solvent, therefore, answer is b).

Best regards.

The statement true about the solution made from a nonvolatile solute and a volatile solvent is, the boiling point of the solution is always greater than the boiling point of the pure solvent. Thus option C is correct.

The boiling point of the solution can be defined as the temperature where the liquid has been converted to the gaseous state. In the solvent, the energy has been provided to the sample for the conversion of liquid molecules to gas.

The addition of a nonvolatile solute to the volatile solvent results in the addition of the molecules to the solvent. This will result in the requirement of more energy for the conversion of solvent from a liquid state to a gaseous state.

Thus, with the addition of a nonvolatile solute to the volatile solvent, the boiling point of the solution will be increased and will always be greater than the boiling point of the pure solvent.

Thus option C is correct.

For more information about the volatile solvent, refer to the link:

https://brainly.com/question/3013635

Answer:

NO.

Explanation:

The rate of diffusion of gases is inversely proportional to the square root of its density as explained by Graham's law of diffusion i.e

Rate (R) & 1/√(density (d))

R & 1/√d

But the density of a gas is proportional to the molar mass (M) of the gas.

Thus, the above equation can written as:

R & 1/√d

R & 1/√M

This implies that rate is inversely proportional to the molar mass of a gas i.e the lighter the gas, the faster the rate and the heavier the gas, the slower the rate of diffusion.

Now, to obtain the answer to the question, let us determine the molar mass of each gas.

This is illustrated below:

Molar mass of Kr = 84 g/mol

Molar mass of NO = 14 + 16 = 30 g/mol

Molar mass of Ar = 40 g/mol

Molar mass of N2O = (14x2) + 16 = 44 g/mol

Summary

Gas >>>>>>> Molar mass

Kr >>>>>>>>> 84 g/mol

NO >>>>>>>> 30 g/mol

Ar >>>>>>>>> 40 g/mol

N2O >>>>>>> 44 g/mol

From the above table, we can see the lightest gas is NO.

Therefore, NO will escape through the hole in the balloon at the highest rate.

Answer:

The correct answer is option C, that is, ΔS and ΔSsurr for the process H2O (s) ⇒ H2O(l) are equal in magnitude and opposite in sign.

Explanation:

The temperature at which solid state of water get transformed into liquid state is termed as the melting point of 0 °C. It can be shown by the reaction:  

H2O (s) ⇒ H2O (l)

The degree of randomness of a molecule is known as entropy. With the transformation of ice into liquid state, there is an increase in randomness. Thus, the value of entropy becomes positive as shown:  

Entropy change (ΔSsys) = ΔSproduct - ΔSreactant

= (69.9 - 47.89) J mol/K

= 22.0 J mol/K

Therefore, the value of entropy change is positive.  

Now the value of entropy for surrounding ΔSsurr will be,  

ΔSsurr = -ΔHfusion/T  

= -6012 j/mol/273

= -22.0 J/molK

Hence, the value of ΔSsurr and ΔSsys exhibit same magnitude with opposite sign.  

Answer: Br-CH₂-CH₂-C≡N (3-bromopropanenitrile)

Explanation:

The question tells us to " Deduce the identity of the following compound from the spectral data given. C3H4BrN: H NMR, δ 2.98 (2H, triplet), 3.53 (2H, triplet) 13C NMR, δ 21.05 (triplet), 23.87 (triplet), 118.08 (singlet) (ppm):JR, 2963, 2254 cm" Express your answer as a chemical formula".

Answer: Another Alternative to this is seen below

The Double Bond Equivalent of C₃H₄BrN = 3+1-4/2-1/2+1/2 = 2

2254 cm-1 Vc ≡N [IR analysis]

2963.4 = sp³Vc-H streek [IR analysis]

where the first CH₂ = b = 2.98 (2H,triplet) and

the second CH₂ = a = 3.53 (2H,triplet)

Note:  where both are 1HNMR.

where C = c = 118.08 (singlet)

CH₂ = b = 21.05 (triplet)

CH₂ = a = 23.87 ( triplet)

Note: where all are 13CNMR

Important:

I have attached a copy of the solution to enhance better understanding in case the typed solution isn't clear enough.

Answer:

33.85°C

Explanation:

From the question,

Heat lost by the hotter water = heat gained by the colder water

cm'(t₂-t₃) = cm(t₃-t₁)................. Equation 1

Where c = specific heat capacity of water, m' = mass of hot water, m = mass of cold water, t₁ = Initial temperature of cold water, t₂ = Initial temperature of hot water, t₃ =  final temperature of the mixture.

But since the density of water is constant, and mass varies directly as volume, We can replace the mass of water with the volume of water. i.e,

cv'(t₂-t₃) = cv(t₃-t₁)................. Equation 2

Where v' and v are the volume of hot water and cold water respectively

make t₃ the subject of the equation

t₃ = (v't₂+vt₁)/(v'+v)............ Equation 3

Given: v' = 5.0 L, v = 60 L, t₁ = 30°C, t₂ = 80°C

Substitute these values into equation 3

t₃ = (5×80+60×30)/(60+5)

t₃ = 2200/68

t₃ = 33.85°C

the products formed from the reaction

all of the above

Answer:

Molality, Solvent, Solute, Mole fraction, Molarity.

Explanation:

The expression of concentration that provides the moles of solute per kilograms of solvent is Molality.  This in the only expression referred to the solvent.

A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the Solvent is water.  When water is present, it is usually considered the solvent.

A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the Solute is sodium chloride.  There can be 1 or more solutes in a solution.

If you place 5 moles of sodium chloride and 4 moles of sucrose into 11 moles of water, the Mole fraction of sodium chloride would be 0.25.  The mole fraction is equal to the moles of a substance divided by the total number of moles.

A way to express concentration that provides the moles of solute per liter of solution is Molarity.

Answer:

The sun warms up parts of the oceans. Warm waters rise just like warm air rises. So, as the warmer ocean waters begin to rise in a particular area, the cooler ocean waters from a different area will move in to replace the warmer ocean waters, and this creates our ocean currents.

Hope it helps!

Answer:

ask a teacher is the correct answer.

Explanation:

You must ALWAYS ask a teacher if you are not sure about what to do during a lab activity.

Answer:

It's important to ask the teacher, lab safety policies all state that if you're confused about instructions it's always good to ask the teacher to clarify them.

Answer:

See explanation below.

Explanation:

We can obtain the Gibb's free energy from the formula;

∆G= ∆H - T∆S

Where;

∆G = change in free energy= the unknown

∆H= change in enthalpy = 3352 kJ

∆S= change in entropy of the solution= 625.1 J/K

T= absolute temperature = 298 K

Substituting values;

∆G= 3352 ×10^3 J - (298 K × 625.1 J/K)

∆G= 3352 ×10^3 J - 186279.8

∆G= 3.16 × 10^6 J

At 5975K,

∆G= ∆H - T∆S

∆G= 3352 ×10^3 J - (5975K × 625.1 J/K)

∆G= 3.352 ×10^6 J - 3.735 × 10^6

∆G= -3.83×10^5 J

At equilibrium, ∆G=0, Teq is given by;

0= 3352 ×10^3 J - (Teq × 625.1 J/K)

0= 3352 ×10^3 - 625.1Teq

625.1Teq = 3352 ×10^3

Teq= 3352 ×10^3/625.1

Teq= 5362.3 K

Standard Gibb's free energy at 298 & 5975K is 3.16×10⁶J and -3.83×10⁵J respectively, and temperature at equilibrium state is 5362.3 K.

Standard Gibb's free energy of any reaction will be calculated as:
∆G° = ∆H° - T∆S°, where

∆G° = change in free energy = to find?

∆H° = change in enthalpy = 3352 kJ = 3,352 × 10³J

∆S° = change in entropy = 625.1 J/K

T = absolute temperature = 298 K

On putting all these values on the above equation, we get

∆G° = (3,352 × 10³) - (298 × 625.1) = 3.16 × 10⁶J

Gibb's free energy at 5,975 K temperature:

∆G° = (3,352 × 10³) - (5,975 × 625.1) = -3.83 × 10⁵J

At the equilibrium state value of Gibb's free energy is zero, so from the equation and given data we can calculate the value of temperature as:

0 = (3352 × 10³)J - (T × 625.1 J/K) = 5362.3 K

Hence required values are 3.16 × 10⁶J, -3.83 × 10⁵J and 5362.3 K.

To know more about Gibb's free energy, visit the below link:

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Answer:

2.41 × 10²⁰ atoms

Explanation:

Step 1: Given data

Step 2: Convert the mass of the sample to grams

We will use the relationship 1 g = 1,000 mg.

38.3 mg × (1 g/1,000 mg) = 0.0383 g

Step 3: Calculate the number of atoms in 0.0383 g of molybdenum

0.0383 g × (1 atom/1.59 × 10⁻²² g) =  2.41 × 10²⁰ atom

Answer:

Metal C

Explanation:

Density = mass (g)/ volume (mL, which is the same thing as cm cubed)

Divide mass by volume for each metal, the metal with the lowest value (metal C) is your answer.

Answer:

IT IS

NOT. I REPEAT - IT IS NOT> D

Explanation:

i got it wrong :(

The correct option is A.

Ordinary sea salt is 97 percent sodium chloride whereas Dead Sea salt is a mixture of lots of different chloride and bromide salts.

Dead Sea Salt differs greatly from other sea salts in mineral content, is made up of sodium chloride with a high percentage of magnesium, sulfates, and potassium. You can bring that ancient, therapeutic experience home with our guaranteed authentic Dead Sea bath salts.

Learn more about salt here https://brainly.com/question/2626194

#SPJ2

Answer:

b. pH=12

Explanation:

Step 1: Given data

Concentration of NaOH: 0.01 mol/dm³ = 0.01 mol/L = 0.01 M

Step 2: Write the reaction for the dissociation of NaOH

NaOH is a strong base that dissociates according to the following equation.

NaOH(aq) ⇒ Na⁺(aq) + OH⁻(aq)

The molar ratio of NaOH to OH⁻ is 1:1. Then, the concentration of OH⁻ is 0.01 M.

Step 3: Calculate the pOH

pOH = -log [OH⁻] = -log 0.01 = 2

Step 4: Calculate the pH

We will use the following expression.

pH + pOH = 14

pH = 14 - pOH = 14 -2 = 12

Answer:

You would use an electrolytic cell.

Answer:

I don't know the second one but one of them is Aristotle

Answer:

Aristrotle and John Dalton

Explanation:

Answer:

HPO₄⁻² +  H₂O  ⇄  PO₄⁻³  + H₃O⁺       Ka3

Explanation:

Phosphoric acid, H3PO4 is a dyprotic acid which undergoes in these three succesive ionization reactions.

The last equillibrium is conditionated to the Ka3

H₃PO₄  +  H₂O  ⇄  H₂PO₄⁻  + H₃O⁺     Ka1

H₂PO₄⁻  +  H₂O  ⇄  HPO₄⁻²  + H₃O⁺   Ka2

HPO₄⁻² +  H₂O  ⇄  PO₄⁻³  + H₃O⁺       Ka3

It is an acid because it release a proton, to make the [H₃O⁺] rise.

pH of solution will always be < 7

H₂PO₄⁻  and  HPO₄⁻²  are amphoteric compounds, which means that they can work as an acid (release protons), or base (take protons)