12. Which formula shows a substance that is not molecular?

H₂

H2O

н

CO2​

The correct answer is mixture

Answer:

Identify each of the following as endothermic or exothermic.

a. Water in a pond evaporates.

b. Methane gas burns on a stovetop.

c. Water freezes to form ice.

d. Energy flows from the system to the surroundings.

e. Energy flows from the surroundings to the system.

Explanation:

An exothermic reaction is the one in which heat energy is released.

An endothermic reaction is one in which heat energy is absorbed.

a. Water in a pond evaporates.

This process absorbs heat energy.

Hence, this is an example of an endothermic process.

b. Methane gas burns on a stovetop and release heat energy and hence this is an example of an exothermic reaction.

c. Water freezes to form ice.

In this process heat energy is released.So this is an example of exothermic reaction.

d. Energy flows from the system to the surroundings.

That means heat energy is released into the surroundings.

So, this is an example of exothermic process.

e. Energy flows from the surroundings to the system.

That means energy is absorbed by the system.

So, it is an endothermic process.

Answer:

7.16 × 10⁻³ M

Explanation:

Let's consider the reduction reaction of copper during the electroplating.

Cu²⁺(aq) + 2 e⁻ ⇒ Cu(s)

We can calculate the moles of Cu²⁺ present in the solution using the following relations.

The moles of Cu²⁺ reduced are:

[tex]2.30 min \times \frac{60s}{1min} \times \frac{3.00C}{s} \times \frac{1mole^{-} }{96486C} \times \frac{1molCu^{2+} }{2mole^{-} } = 2.15 \times 10^{-3} molCu^{2+}[/tex]

[tex]2.15 \times 10^{-3} moles[/tex] of Cu²⁺ are in 0.300 L of solution.

[Cu²⁺] = 2.15 × 10⁻³ mol/0.300 L = 7.16 × 10⁻³ M

Answer:

1. 306,000: three significant figures because the last three zeros are not preceded by a decimal point.

2. 0.0073: two significant figures because the the leftmost zeros are not significant.

3. 39.9999: six significant figures because all these numbers are nonzero digits.

4. 25.00: four significant figures because right-handed zeros, after a decimal point, are significant.

5. 40,000,021: eight significant figures because intermediate zeros are significant.

6. 45,250.0: six significant figures because al the zeros are to the right of the nonzero digits.

7. 0.00011: two significant figures as well as #2.

8. 420.030700: nine significant figures because all the zeros are to the right of the first nonzero digits and after the decimal point.

Explanation:

Hello there!

In this case, by considering the given numbers, we can proceed as follows, by keeping in mind the rules for assigning significant figures:

1. 306,000: three significant figures because the last three zeros are not preceded by a decimal point.

2. 0.0073: two significant figures because the the leftmost zeros are not significant.

3. 39.9999: six significant figures because all these numbers are nonzero digits.

4. 25.00: four significant figures because right-handed zeros, after a decimal point, are significant.

5. 40,000,021: eight significant figures because intermediate zeros are significant.

6. 45,250.0: six significant figures because al the zeros are to the right of the nonzero digits.

7. 0.00011: two significant figures as well as #2.

8. 420.030700: nine significant figures because all the zeros are to the right of the first nonzero digits and after the decimal point.

Regards!

The element nitrogen exists as a gas  and is  obtained from air on a large scale​ by fractional distillation of air.

An element is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.

Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.

The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.

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Answer:

d. 4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)

Explanation:

Aluminum metal reacts with oxygen gas in a combination reaction that forms a product that coats the metal preventing it from further oxidation: aluminum oxide. Aluminum is a cation with charge 3+ (Al³⁻) and oxide is an anion with charge 2- (O²⁻). Thus, the neutral compound aluminum oxide has the chemical formula Al₂O₃. The unbalanced chemical equation is:

Al(s) + O₂(g) → Al₂O₃(s)

We can balance using the trial and error method. First, we will balance O atoms by multiplying Al₂O₃ by 2 and O₂ by 3.

Al(s) + 3 O₂(g) → 2 Al₂O₃(s)

Finally, we get the balanced equation by multiplying Al by 4.

4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)

Answer:

25%

Explanation:

Cystic fibrosis is a recessive allele, meaning that the child must be aa to suffer the symptoms. Only 1/4 of the paired alleles is aa, so the probability of getting cystic fibrosis would be 25%.

Answer:

See explanation

Explanation:

The electrophilic substitution of aromatic compounds occurs faster in substituted aromatic compounds due to the fact that the ring becomes more or less susceptible to electrophilic attack depending on the nature of the substituent in the ring.

Electron pushing substituents such as alkyl groups stabilize the positive charge developed during electrophilic substitution hence they activate the ring towards electrophilic substitution.

The methyl group is an ortho - para directing substituent hence the product obtained by nitration of toluene is o-nitrotoluene and p-nitrotoluene.

The stepwise mechanism for obtaining these products is shown in the image attached to this answer.

Answer:

potentiol or kenetic

Explanation:

Answer:

36704 $

Explanation:

First we calculate how much the worker gets paid in one week:

Then we calculate how many weeks does the worker work in 1.7 years:

Finally we calculate how much does the worker make in 1.7 years:

Answer:

The three freezing points will all be slightly different. It is given that a water solution has a freezing point of zero degrees Celsius, so water would have a freezing temperature below that. Salt will lower the freezing point, the more that is added.

Explanation:

Answer:

40.4 kJ

Explanation:

Step 1: Given data

Step 2: Calculate the moles corresponding to 55.0 g of CO₂

The molar mass of CO₂ is 44.01 g/mol.

n = 55.0 g × 1 mol/44.01 g = 1.25 mol

Step 3: Calculate the heat (Q) required to sublimate 1.25 moles of CO₂

We will use the following expression.

Q = n × ΔH°sub

Q = 1.25 mol × 32.3 kJ/mol = 40.4 kJ

Answer: The value of i is 1.4 and 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.

Explanation:

The equation used to calculate the Vant' Hoff factor in dissociation follows:

[tex]\alpha =\frac{i-1}{n-1}[/tex]

where,

[tex]\alpha [/tex] = degree of dissociation = 40% = 0.40

i = Vant' Hoff factor

n = number of ions dissociated = 2

Putting values in above equation, we get:

[tex]0.40=\frac{i-1}{2-1}\\\\0.40=i-1\\\\i=1.4[/tex]

The equation used to calculate the degee of dissociation follows:

[tex]\alpha =\frac{\text{Number of particles dissociated}}{\text{Total number of particles taken}}[/tex]

Total number of particles taken = 100

Degree of dissociation = 40% = 0.40

Putting values in above equation, we get:

[tex]0.40=\frac{\text{Number of particles dissociated}}{100}\\\\\text{Number of particles dissociated}=(0.40\times 100)=40[/tex]

This means that 40 particles are dissociated and 60 particles remain undissociated in the solution.

Hence, 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.

Answer:

A. Mass of KMnO₄ = 316.08 g

B. Mass of KMnO₄ = 41.49 g

C. Mass of KMnO₄ = 0.13 g.

Explanation:

A. Determination of the mass of KMnO₄

We'll begin by determining the number of mole of KMnO₄ in the solution. This can be obtained as follow:

Volume = 1 L

Molarity = 2 M

Mole of KMnO₄ =?

Mole = Molarity × Volume

Mole of KMnO₄ = 2 × 1

Mole of KMnO₄ = 2 moles

Finally, we shall determine the mass of KMnO₄. This can be obtained as follow:

Mole of KMnO₄ = 2 moles

Molar mass of KMnO₄ = 158.04 g/mole

Mass of KMnO₄ =?

Mass = mole × molar mass

Mass of KMnO₄ = 2 × 158.04

Mass of KMnO₄ = 316.08 g

B. Determination of the mass of KMnO₄

We'll begin by determining the number of mole of KMnO₄ in the solution. This can be obtained as follow:

Volume = 350 mL = 350/1000 = 0.35 L

Molarity = 0.75 M

Mole of KMnO₄ =?

Mole = Molarity × Volume

Mole of KMnO₄ = 0.75 × 0.35

Mole of KMnO₄ = 0.2625 mole

Finally, we shall determine the mass of KMnO₄. This can be obtained as follow:

Mole of KMnO₄ = 0.2625 mole

Molar mass of KMnO₄ = 158.04 g/mole

Mass of KMnO₄ =?

Mass = mole × molar mass

Mass of KMnO₄ = 0.2625 × 158.04

Mass of KMnO₄ = 41.49 g

C. Determination of the mass of KMnO₄

We'll begin by determining the number of mole of KMnO₄ in the solution. This can be obtained as follow:

Volume = 80 mL = 80/1000 = 0.08 L

Molarity = 0.01 M

Mole of KMnO₄ =?

Mole = Molarity × Volume

Mole of KMnO₄ = 0.01 × 0.08

Mole of KMnO₄ = 0.0008 mole

Finally, we shall determine the mass of KMnO₄. This can be obtained as follow:

Mole of KMnO₄ = 0.0008 mole

Molar mass of KMnO₄ = 158.04 g/mole

Mass of KMnO₄ =?

Mass = mole × molar mass

Mass of KMnO₄ = 0.0008 × 158.04

Mass of KMnO₄ = 0.13 g

Answer:

180 amu

C₆H₁₂O₆

Explanation:

Step 1: Determine the molecular mass of the compound

The sample has a mass (m) of 3.06 g and it contains (n) 0.0170 moles. The molar mass M is:

M = m/n = 3.06/0.0170 mol = 180 g/mol

Then, the molecular mass is 180 amu.

Step 2: Determine the molar mass of the empirical formula.

M(CH₂O) = 1 × M(C) + 2 × M(H) + 1 × M(O)

M(CH₂O) = 1 × 12 g/mol + 2 × 1 g/mol + 1 × 16 g/mol = 30 g/mol

Step 3: Determine the molecular formula

First, we will determine "n" according to the following expression.

n = molar mass molecular formula / molar mass empirical formula

n = 180 g/mol / 30 g/mol = 6

The molecular formula is:

n × CH₂O = 6 × CH₂O = C₆H₁₂O₆

Answer:

7505.19 J

Explanation:

We'll begin by calculating the change in the temperature of copper. This can be obtained as follow:

Initial temperature (T₁) = 20 °C

Final temperature (T₂) = 875 °C

Change in temperature (ΔT) =?

ΔT = T₂ – T₁

ΔT = 875 – 20

ΔT = 855 °C

Finally, we shall determine the heat required. This can be obtained as follow:

Specific heat capacity (C) = 0.385 J/gºC

Change in temperature (ΔT) = 855 °C

Mass (M) = 22.8 g

Heat (Q) required =?

Q = MCΔT

Q = 22.8 × 0.385 × 855

Q = 7505.19 J

Thus, 7505.19 J of heat energy is required.

Answer:

2.5 × 10² ppm

Explanation:

Step 1: Given data

Step 2: Convert 0.050 g to μg

We will use the conversion factor 1 g = 10⁶ μg.

0.050 g × 10⁶ μg/1 g = 5.0 × 10⁴ μg

Step 3: Calculate the concentration of NaCl in ppm

The concentration of NaCl in ppm is equal to the micrograms of NaCl per gram of the sample.

5.0 × 10⁴ μg NaCl/200. g = 2.5 × 10² ppm

Answer:250 ppm

Explanation:

Answer:

37.85 L

Explanation:

3.785 x 10.00 = 37.85 L

it would take 37.85 L  to fill a 10.00 tank

(sorry if im wrong pls dont report)

(hope this helps can i plz have brainlist :D hehe)

Answer: In the reaction:

a) The reactants are: P

b) The products are: M and N

Explanation:

The given reaction equation is as follows.

[tex]P \rightarrow M + N[/tex]

Reactants are the species present on the left side on an arrow in a chemical reaction equation.

On the other hand, products are the species which are present on the right side of an arrow in a chemical reaction equation.

Hence, in the given reaction equation P is the reactant. Whereas M and N are the products.

Thus, we can conclude that in the reaction:

a) The reactants are: P

b) The products are: M and N

Answer:

25.46 mL

Explanation:

In a titration we use the volume and concentration of a solution to determine the previously unknown concentration of other solution. Let's consider the titration of an acid of unknown concentration with a standardized base (a base whose concentration we know). The generic neutralization reaction is:

HA + BOH ⇒ BA + H₂O

The base is in the buret and we will add it to the acid until the equivalence point is reached. The volume of base used is equal to the difference between the final reading of the buret and the initial reading of the buret.

V = 27.30 mL - 1.84 mL = 25.46 mL

Answer:

false

Explanation:

energy does not return to the sun, it returns to the plants or producers. if energy were to return to the sun, it would have to travel though space.

Answer:

A) Electrons orbit the nucleus in shells at fixed distances

Answer:

the answer is A

Explanation:

Answer:

d . The volume of the solvent used was less than 5 liters.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the volume of the stock (initial) solution by using the following equation:

[tex]M_1V_1=M_2V_2[/tex]

Thus, we solve for, V1, which stands for the aforementioned volume of stock solution:

[tex]V_1=\frac{M_2V_2}{M_1}[/tex]

Then, we plug in to obtain:

[tex]V_1=\frac{5L*1M}{10M}\\\\V_1=0.5L[/tex]

Now, since the final volume was 5 L, we can infer that the volume of solvent is 4.5 L and that of the stock solution 0.5 L for a total of 5 L of diluted solution; therefore, the correct reasoning is d . The volume of the solvent used was less than 5 liters.

Regards!

Answer:

The volume of the solvent is less than 5

Explanation:

Answer:

the value of H° is below -6535 kj. +6H2O

Explanation:

6H2O answer solved

For the given reaction, 2 moles of C₆H₆ the heat energy released is - 6535 KJ. Then, for 16 g of the compound or 0.205 moles needs 669.83 KJ of heat released in combustion.

Combustion is a chemical reaction that occurs between a fuel and an oxidizing agent, typically oxygen, resulting in the release of heat, light, and various combustion products, such as carbon dioxide and water vapor.

The process of combustion involves a rapid and exothermic (heat-releasing) oxidation reaction that produces a flame, which is visible in many cases.

Here, 2 moles of the hydrocarbon releases - 6535 KJ of energy.

molar mass of C₆H₆ = 78 g/mol

then no.of moles in 16 g = 16 /78 = 0.205 moles.

then energy released by 0.205 moles  = 0.205 moles × 6535 KJ /2 moles = 669.83 kJ

Therefore, the heat energy released by 16 g of the compound in combustion is 669.83 kJ.

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Answer:

The more concentrated acetic acid buffer has a better buffer capacity because requires more moles of acid or base to change the pH than a more diluted acetic acid buffer.

Explanation:

Buffer capacity is defined as the moles of an acid or base that are needed to change the pH of a buffer in 1 unit.

A more concentrated solution of acetic buffer contains more moles of the acid per liter of solution. A solution that contains more moles of the acetic ion or the acetic acid requires more moles of base or acid to change the pH, that means:

The more concentrated acetic acid buffer has a better buffer capacity because requires more moles of acid or base to change the pH than a more diluted acetic acid buffer.

Answer: hello your question is poorly written below is the complete question

answer:

For N1 :  sp³  orbital

For N2:  p orbital

For N3 : p orbital

For N4 : sp² orbital

For N5 : sp² orbital

Explanation:

Determining the type of orbital in which the lone pair on each N atom will reside.

From the configuration attached below we can determine the type of orbital and they are ;

For N1 :  sp³  orbital

For N2:  p orbital

For N3 : p orbital

For N4 : sp² orbital

For N5 : sp² orbital

Answer:

i didnt understand

Explanation:

Answer:

x = 2 (C₂H₆)

Explanation:

The general formula for alkanes is CₓH₂ₓ₊₂

2x + 2 = 6

Simply solve for n:

2x = 4

x = 2

Answer:

false all producers are at the top of food web