plz help on both I will mark brainest and explain how you got it ​

Answer:

ΔH°rxn = -827.5 kJ

Explanation:

Let's consider the following balanced equation.

2 PbS(s) + 3 O₂(g) → 2 PbO(s) + 2 SO₂(g)

We can calculate the standard enthalpy of reaction (ΔH°rxn) from the standard enthalpies of formation (ΔH°f) using the following expression.

ΔH°rxn = [2 mol × ΔH°f(PbO(s)) + 2 mol × ΔH°f(SO₂(g) )] - [2 mol × ΔH°f(PbS(s)) + 3 mol × ΔH°f(O₂(g) )]

ΔH°rxn = [2 mol × ΔH°f(PbO(s)) + 2 mol × ΔH°f(SO₂(g) )] - [2 mol × ΔH°f(PbS(s)) + 3 mol × ΔH°f(O₂(g) )]

ΔH°rxn = [2 mol × (-217.32 kJ/mol) + 2 mol × (-296.83)] - [2 mol × (-100.4) + 3 mol × 0 kJ/mol]

ΔH°rxn = -827.5 kJ

The standard enthalpy of the reaction is -827.5 kJ/mol

The standard enthalpy of reaction [tex]\mathbf{\Delta H^0_{rxn}}[/tex] is the enthalpy change that happens in a system whenever one mole of the matter is converted through a chemical process under normal conditions.

The given reaction can be expressed as:

2PbS(s) + 3O₂(g) → 2PbO(s) + 2SO₂(g)

The standard enthalpy can be represented by the equation:

[tex]\mathbf{\Delta H^0_{rxn} = \sum \Delta _f ^0(products) - \sum \Delta _f^0(reactants)}[/tex]

At standard conditions, the standard enthalpies of formation of the given species are:

∴

[tex]\mathbf{ \Delta H^0_{rxn} = \Big[2 mol \times \Delta H^0_f(PbO(s)) + 2 mol \times \Delta H^0_ f(SO_2(g) )\Big] - \Big[2 mol \times \Delta H^0_f (PbS(s))} + \mathbf{ 3 mol \times \Delta H^0_f(O_2(g) )\Big] }}[/tex]

[tex]\mathbf{\Delta H^0rxn = [2 mol \times (-217.32 kJ/mol) + 2 mol \times (-296.83)] - [2 mol \times (-100.4)} \\ \mathbf{+ 3 mol \times 0 kJ/mol]}}[/tex]

[tex]\mathbf{\Delta H^0rxn = -827.5 \ kJ/mol}}[/tex]

Therefore, we can conclude that the standard enthalpy of the reaction is -827.5 kJ/mol

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Answer:

Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes.

Explanation:

Answer:

Hope this helped.

Explanation:

Cellulose is a molecule, consisting of hundreds – and sometimes even thousands – of carbon, hydrogen and oxygen atoms. Cellulose is the main substance in the walls of plant cells, helping plants to remain stiff and upright. Humans cannot digest cellulose, but it is important in the diet as fibre.

Answer:

True

Explanation:

Because atoms with the same number of valence electrons react in similar ways with other elements.

Answer:

Explanation:

pH = 10.3

[ H] = 10⁻¹⁰°³

= 5 x 10⁻¹¹ M

concentration of CsOH C = 3 M

pKa of carbonate = 6.35

Ka = 10⁻⁶°³⁵ = 4.46 x 10⁻⁷

Buffer capacity = 2.303 x C x Ka x [ H⁺] / ( Ka + [ H⁺]² )²

= 2.303 x 3 x 4.46 x 10⁻⁷  x 5 x 10⁻¹¹ / ( 4.46 x 10⁻⁷  + 25 x 10⁻²² )²

= 154 x 10⁻¹⁸ / 19.9 x 10⁻¹⁴

= 7.74 x 10⁻⁴ .

Answer:

The sun's light is blocked by the moon.

Explanation:

During the eclipse, the moon rotates right in front of the sun, that's why the eclipse is so rare and only happens every four(?) years/

Answer:

Ka = 4.70x10⁻⁴M

Explanation:

The general dissociation of a weak acid, HX, is:

HX(aq) ⇄ H⁺(aq) + X⁻(aq)

And Ka is written as:

Ka = [H⁺] [X⁻] / [HX]

Where [] represents the molar concentration in equilibrium of each specie.

The equilibrium is reached when X of HX is dissociate in X H⁺ and X X⁻, that is:

[HX] = 0.0129M - X

[H⁺] = X

[X⁻] = X

As pH = -log [H⁺]:

10^-pH = [H⁺] = X  = 2.239x10⁻³M

Solving:

[HX] = 0.0129M - 2.239x10⁻³M = 0.01066M

[H⁺] = 2.239x10⁻³M

[X⁻] = 2.239x10⁻³M

Ka = [H⁺] [X⁻] / [HX]

Ka = [2.239x10⁻³M] [2.239x10⁻³M] / [0.01066M]

Answer:

its C and D

C. The brown substance is molecular

D. The blue substance is ionic

Explanation:

did the test !

Two correct statements are B) The silver substance is ionic

C) The brown substance is molecular.

Silver is a chemical element with the symbol Ag and atomic wide variety 47. categorized as transition steel, Silver is stable at room temperature.

It is a molecular substance, that's a substance with or more atoms, the smallest gadgets of remember joined together via a covalent bond. A covalent bond is a hyperlink created via the sharing of electrons that holds these atoms collectively.

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It is critical to watch or observe what is happening with every step of your experiment

Answer:

Red

Explanation:

Acetic acid is an acidic medium. Recall that indicators are organic substances whose color changes in response to change in the pH of the solution. often times, the protonated and deprotonated forms of an indicator have different colors.

However, an equilibrium is set up when an indicator is in acid/ basic medium. Methyl orange is red in acid medium and yellow in  basic medium.

Hence while in acetic acid, the equilibrium lies towards the protonated form of acetic acid, hence the solution appears red.

Answer:

The answer is true

Explanation:

bc I took this on edgeunity

Complete Question

The complete question is shown in the first uploaded image

Answer:

So the math expression is  

             [tex]heat  =  \frac{ 35. 7  KJ *  1900 \ gram }{ 1 \ gram }[/tex]

Explanation:

From the question we are told that

  The heat released for 1 gram of reactant consumed is  [tex]H  =  37.5 \ KJ/g [/tex]

   The mass of reactant considered is  [tex]m =  1.9 \ kg  =  1900 \  g[/tex]

So  if

             [tex]37.5 \ KJ [/tex] is produced for  1 gram

Then

              x kJ is produced for  1900 g  

=>   [tex]x  =  \frac{ 35. 7  KJ *  1900 \ gram }{ 1 \ gram }[/tex]

So the heat released is  

       [tex]heat  =  \frac{ 35. 7  KJ *  1900 \ gram }{ 1 \ gram }[/tex]

Answer:

true. cathode rays are deflected

Answer:

a. H₂CO₃(aq) + KOH(aq) ⇄ K₂CO₃(aq) + H₂O(l)

b. 0.603 M

Explanation:

Step 1: Write the neutralization reaction

H₂CO₃(aq) + KOH(aq) ⇄ K₂CO₃(aq) + H₂O(l)

Step 2: Calculate the reacting moles of KOH

22.9 mL of 1.430 M KOH react.

0.0229 L × (1.430 mol/L) = 0.0327 mol

Step 3: Calculate the reacting moles of H₂CO₃

The molar ratio of H₂CO₃ to KOH is 1:1. The reacting moles of H₂CO₃ are 1/1 × 0.0327 mol = 0.0327 mol.

Step 4: Calculate the molarity of H₂CO₃

0.0327 moles of H₂CO₃ are in a volume of 54.2 mL. The molarity of H₂CO₃ is:

M = 0.0327 mol/0.0542 L = 0.603 M

Answer:

2016 Km.

Explanation:

The following data were obtained from the question:

Speed (S) = 1.12×10⁴ m/s

Time (t) = 3 mins

Distance (d) =.?

Next, we shall convert 3 mins to seconds. This can be obtained as follow:

1 min = 60 s

Therefore,

3 mins = 3 min × 60 s / 1 min

3 mins = 180 s

Next, we shall determine the distance travelled by the rocket. This is illustrated below:

Speed (S) = 1.12×10⁴ m/s

Time (t) = 180 s

Distance (d) =.?

Speed (S) = distance (d) /time (t)

S = d/t

1.12×10⁴ = d/ 180

Cross multiply

d = 1.12×10⁴ × 180

d = 2016000 m

Finally, we shall convert 2016000 m to Km. This can be obtained as shown below:

1000 m = 1 Km

Therefore,

2016000 m = 2016000 m × 1 Km / 1000 m

2016000 m = 2016 Km

Therefore, the rocket will travel 2016 Km in 3 mins

Answer:

try dividing the grams and the volume and see what number matches up with your answer

Answer:

Answer:

36 mol of H2

Explanation:

The balanced equation of the reaction is given as;

3H2 + N2 --> 2NH3

From the reaction;

It takes 3 mol of H2 reacting with 1 mol  of N2 to form 2 mol of NH3

3 mol of H2 = 2 mol of NH3

x mol of H2 = 24 mol of NH3

x =  (24 * 3) / 2 = 36 mol of H2

Answer:

no d

Explanation:

it has a permanent dipole

CH₃F compound contains polar covalent bonds in its structure, hence option D is correct.

This happens when the electronegativity of the relevant atoms differs significantly.

The electronegativities of the carbon and fluorine atoms in CH3F are dissimilar. Because fluorine is more electronegative than carbon, it attracts the shared electrons to it, giving the fluorine atom a partial negative charge and the carbon atom a partial positive charge.

A polar covalent bond is created as a result of this unequal charge distribution. CH₃F compound contains polar covalent bonds in its structure.

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Answer:

The plant uses carbon dioxide and water to make an entirely new chemical hence chemical change.

Explanation:

Plants create their own 'food', they turn carbon dioxide water and sunlight to create starch and glucose..

Answer:

The properties of carbon dioxide and oxygen are different.

Explanation:

im taking the exam right now and Im pretty sure it's D The properties of carbon dioxide and oxygen are different.

Answer:

Explanation:

Al(s) + 3/2 Br₂(l) = AlBr₃(s)

K = [  AlBr₃] / [ Al] [  Br₂]³/²

K² =  [  AlBr₃]² / [  Al ] ² [ Br₂]³

2 AlBr₃ = 2 Al(s) + 3 Br₂(l) =

K₁ =  [  Al ] ² [ Br₂]³ /  [  AlBr₃]²

K₁ =  ( 1 / K² ) = K⁻²

2 ) 2 Al(s) + 3 Br₂(l) = 2 AlBr₃(s)

K₂ = [ AlBr₃ ]² / [  Al ]² [  Br₂ ]³

K₂ = K²

3 )

AlBr₃(s) =   Al(s) + 3/2 Br₂(l)

K₃  = [ Al ] [ Br₂ ] ³/² / [ AlBr₃ ]

=  ( 1 / K ) = K⁻¹

The mass number of an element is the sum of the protons and neutrons present in the nucleus of the atoms of the element.

The mass number of an element is the number obtained when the number of protons and neutrons in the nucleus of an atom of the element are summed together.

The sum of protons and neutrons in the nucleus of an atom is collectively known as the nucleon. Thus, the mass number of an atom can also be referred to as the nucleon of the atom.

This can be mathematically expressed as:

Mass number = number of protons + number of neutrons.

Atoms generally contain protons, neutrons, and electrons. The protons are positively charged and are located in the nucleus, the neutrons are also located in the neucleus but have no charges. The electrons, on the other hand, are located outside the nucleus in regions referred to as orbitals.

The sum of the protons and neutrons determine the mass of an atom because the contribution of electrons to the mass of atoms is negligible.

Thus, the mass number of an element is the sum of proton and neutron numbers present in the nucleus of the atoms of the element.

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Answer:

d

Explanation:

collagen is made of proteins

Answer:

1.24 L of H₂ at STP .

Explanation:

2Al(s)    +6HCl(aq)    →    2AlCl₃(aq)   +    3H₂(g)

2 moles                                                  3 x 22.4 L

2 x 27 g of Al reacts to give  3 x 22.4 L of H₂ at STP .

1 g of Al will react to give 3 x 22.4 / ( 2 x 27 ) L of H₂ at STP .

= 1.24 L of H₂ at STP .

The volume of hydrogen produced by 1 grams of Al has been 1.24 L.

The balanced chemical reaction has been given as:

[tex]\rm 2\;Al\;+\;6\;HCl\;\rightarrow\;2\;AlCl_3\;+\;3\;H_2[/tex]

From the equation, 2 moles of Aluminum gives 3 moles of Hydrogen

The mass of the compound from moles can be given as:

Mass = moles × molecular mass

Mass of 2 moles Al = 2 × 27 g

Mass of 2  moles Al = 54 g

Mass of 3 moles hydrogen = 3 × 2 g

Mass of 3 moles hydrogen = 6 g

From the equation,

54 g aluminum gives = 6 grams hydrogen

[tex]\rm 1\;gram\;aluminum\;=\;\dfrac{6}{54}\;\times\;1[/tex]

1 gram Aluminum = 0.11 grams hydrogen

The mass of hydrogen produced by 1 gram Al has been 0.11g. The moles equivalent to 0.11g hydrogen has been given as:

Mass = moles × molecular mass

0.11 g = moles × 2 g/mol

Mole of hydrogen = 0.055 mol

The moles of hydrogen produced by 1 gram of Al has been 0.055 mol.

According to the ideal gas equation, any gas at STP has 1 mole equivalent to 22.4 L. So,

1 mol = 22.4 L

0.055 mol = 0.055 × 22.4 L

0.055 mol = 1.244 L.

The volume of hydrogen produced by 1 grams of Al has been 1.24 L.

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