Question 10 of 10

Multiple Choice: Please select the best answer and click "submit."

During a lightning storm, the Jones family notices their computer has shut off. When they turn it back on, it functions properly. What should they buy to protect their computer during future lightning storms?

A. A surge protector
B. A circuit board
C. A power surge
D. A ground wire

Answer : Option C) Krypton - 84

Explanation : The average atomic mass recorded on the periodic table for krypton is 83.80 u. This indicates that the most abundant isotope of krypton is Krypton - 84.

As the natural abundance of krypton - 84 is higher than the other isotopes of the krypton, which is 56.99 percent. This the most stable form of Kr that exists in nature. Rest other isotopes are not that readily available and also not that stable as compared to Krypton - 84.

Krypton - 83 has natural abundance as 11.50 percent and krypton - 82 has natural abundance 11.59 percent.

So, this clearly explains that the most abundant krypton isotope is Krypton - 84.

Answer: We need 0.216 moles of Ba(OH)2 to completely neutralize 0.432 moles of HC2H3O2.

Explanation:

2 CH3COOH + Ba(OH)2 = Ba(Ch3COO)2 + 2 H2O

0.432moles CH3COOH x [1 mol Ba(OH)2/ 2 moles CH3COOH]  = 0.216 moles Ba(OH)2

Answer:

348

Explanation:

Answer: The correct answer is-

Flow of energy in an ecosystem ( a large community of life forms that interact with each other as well as their physical environment in a particular area) takes place through food chain.

A food chain is a linear network of different organisms ( occupying different trophic levels) where organisms at one trophic level consumes organisms at previous trophic level and energy flow takes place in the form of organic matter.

Producers ( such plants) prepare their own food through photosynthesis and occupy the first trophic level.

Producers are eaten by primary consumers ( which are generally herbivores such as rabbits).

Primary consumers are eaten by secondary consumers, which are then eaten by tertiary consumers that are eaten by final consumers and then decomposers ( such as Fungi).

Example- Grass → Grasshopper → Frog→ Snake → Hawk → Fungi

The Earth is composed of four different layers. Many geologists believe that as the Earth cooled the heavier, denser materials sank to the center and the lighter materials rose to the top. Because of this, the crust is made of the lightest materials (rock- basalts and granites) and the core consists of heavy metals (nickel and iron).

Answer: Option (c) is the correct answer.

Explanation:

According to law of conservation of energy, energy can neither be created nor it can be destroyed as it can only be converted from one form to another.

For example, in the given situation electrical energy is converted into heat energy.

This means that the total amount of the electrical energy is actually equal to the total amount of heat energy. As only change in the form of energy has taken place.

Thus, we can conclude that as electrical energy is converted into heat energy, the total amount in the system remains the same.

Final answer:

The temperature records show that high and low temperatures have varied over time and location, with Chicago experiencing its highest at 105° in July 1995 and lowest at -27° in January 1958. The general temperature trend has shifted towards more common record high temperatures and less frequent record lows since the 1970s. Analyzing longstanding patterns is essential to understanding climate trends and making future predictions.

Explanation:

When analyzing the highest and lowest temperatures on record, several factors must be considered, such as temporal scope and geographic location. For example, in Chicago, Illinois, the highest recorded temperature was 105° in July 1995, and the lowest recorded temperature was -27° in January 1958. When reviewing temperature data over a broader historical timeline, such as the past 4.5 billion years, we see that high temperature peaks and average global temperatures at those peaks have varied significantly and are indicative of major climatic shifts.

The daily temperature range, which is the difference between the highest and lowest temperatures over a 24-hour period, can provide a more immediate understanding of temperature variation. Additionally, graphs showing temperature trends may identify specific periods with extreme temperature fluctuations, such as the highs and lows recorded during glacial and interglacial periods.

The general trend in temperature, particularly since the 1970s, shows that record-setting daily high temperatures have become more common, and unusually cold temperatures, especially during the winter, have become less common. Such patterns can provide critical insights into the ongoing discussion about climate change and global warming. While singular record highs or lows are noteworthy, analyzing the entire pattern of temperature data over time is crucial for understanding typical weather patterns and predicting future climatic changes.

The number of moles in 17.0g sodium chloride is 0.291 moles

In the International System of Units, Mole is the base unit of the amount of any substance.

The mass of NaCl is 17.0 g

The molar mass of Na is 22.99 g/mol

The molar mass of Cl is 35.45 g/mol

The molar mass of NaCl will be

(22.99 g/mol + 35.45 g/mol) = 58.44 g/mol

[tex]\rm Number\;of \;moles= \dfrac{mass}{molar\;mass}\\\\\\\rm Number\;of \;moles= \dfrac{17.0 g}{58.44\; g/m} =0.291 mol[/tex]

Thus, the number of moles in 17.0g sodium chloride is 0.291 moles.

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Answer:

200 grams, because all the atoms remain in the balloon or flask.

Explanation:

I got a 95 on usatestprep

Final answer:

The total mass of the balloon and flask remains 200 grams after the balloon inflates due to the Law of Conservation of Mass, as no mass is lost to the surroundings during the chemical reaction between vinegar and baking soda.

Explanation:

The total mass of the flask with vinegar and the balloon with baking soda will remain the same before and after the balloon inflates. When the vinegar and baking soda mix, they undergo a chemical reaction that produces carbon dioxide gas, which inflates the balloon. According to the Law of Conservation of Mass, the mass of the reactants (vinegar and baking soda) must equal the mass of the products (the contents of the balloon and flask after the reaction). Therefore, if the flask with vinegar initially has a mass of 160 grams and the balloon with baking soda has a mass of 40 grams, the combined mass before the reaction is 200 grams. After the reaction, even though gas has filled the balloon and caused it to inflate, the total mass of the system remains unchanged at 200 grams, assuming the reaction is completely contained within the balloon and flask with no loss of mass to the surroundings.

Answer:

c) Fractional distillation

Explanation:

A common method used to separate liquid solutions is fractional distillation.

In this process a mixture of two or more liquids that differ in their boiling points are heated. The liquid with the lowest boiling point vaporizes first which is passed onto a condenser and separated out. The same process ensues for the next liquid component until all are separated out in fractions based on their respective boiling points.

For example, consider a mixture of ethanol (b.pt 78 C) and water (b.pt 100 C). The two liquids can be separated by heating the mixture, in which ethanol separates out first followed by water.

To produce 19.1 moles of water vapor when carbon dioxide is in excess, 19.1 moles of hydrogen gas are needed, based on the stoichiometry of the water-gas shift reaction.

To determine how many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 19.1 moles of water vapor, we need to consider the balanced chemical equation for the reaction. The reaction in question is not stated, but it is likely a form of the water-gas shift reaction, which is:

CO2 + H2 → CO + H2O

From the equation, we can see that for every mole of H2O produced, one mole of H2 is required, assuming that carbon dioxide (CO2) is in excess.

Therefore, if we have 19.1 moles of water vapor (H2O), we need 19.1 moles of hydrogen gas (H2).

Final answer:

To produce 19.1 moles of water vapor by reacting hydrogen gas with excess carbon dioxide, 19.1 moles of hydrogen gas would be required, assuming a 1:1 stoichiometry.

Explanation:

To determine how many moles of hydrogen gas are needed to react with excess carbon dioxide to produce 19.1 moles of water vapor, we need to consider the balanced chemical equation:

H₂ (g) + CO₂ (g) → H₂O (g) + CO (g)

However, the provided examples do not directly address this reaction. Instead, we can deduce from the given information that:

In a similar vein, if we assume the reaction consuming hydrogen and carbon dioxide produces water and carbon monoxide in a 1:1 stoichiometry (as in the Sabatier process), we have:

H₂ (g) + CO₂ (g) → H₂O (g) + CO (g)

For every mole of water produced, one mole of hydrogen is required. Therefore, for 19.1 moles of water, 19.1 moles of hydrogen gas are needed.

Answer:

200 g/mol is the molar mass of the unknown gas.

Explanation:

Effusion is defined as volume of gas dispersed in a given interval of a time.

[tex]R=\frac{Volume}{time}[/tex]

Number of moles of gas are directly proportional to the volume occupied by the gas.

[tex]moles \propto Volume[/tex] (at constant temperature and pressure)

[tex]\frac{n_1}{V_1}=\frac{n_2}{V_2}[/tex]

If n moles of unknown gas occupies V volume then n moles of oxygen will occupy:

[tex]V_1=\frac{n\times V}{n}=V[/tex]

The n moles of unknown gas pass through a tiny hole in 75 seconds.The effusion rate is give as:

[tex]R=\frac{V}{75 s}[/tex]

The n moles of oxygen gas pass through a tiny hole in 30 seconds.The effusion rate is give as:

[tex]R'=\frac{V}{30 s}[/tex]

According to Graham law: the effusion rate is inversely proportional to the square root of molar mass of the gas.

[tex]\frac{R}{R'}=\sqrt{\frac{32 g/mol}{M}}[/tex]

[tex]\frac{\frac{V}{75 s}}{\frac{V}{30 s}}=\sqrt{\frac{32 g/mol}{M}}[/tex]

[tex]M=\frac{32 g/mol\times 75\times 75}{30 \times 30}=200 g/mol[/tex]

200 g/mol is the molar mass of the unknown gas.

The molar mass of the unknown gas that diffused in the experiment is 200 g/mol.

The given parameters;

The rate of diffusion of the gases is calculated using Graham's law of diffusion as follows;

[tex]\frac{R_1}{R_2} = \frac{t_2}{t_1} = \sqrt{\frac{M_2}{M_1} } \\\\(\frac{t_2}{t_1} )^2 = \frac{M_2}{M_1} \\\\(\frac{30}{75})^2 = \frac{32}{M_1} \\\\0.16 = \frac{32}{M_1} \\\\M_1 = \frac{32}{0.16} \\\\M_1 = 200 \ g/mol[/tex]

Thus, the molar mass of the unknown gas that diffused in the experiment is 200 g/mol.

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c. this is the real answer lol

Final answer:

A book is sitting on the table at rest. The forces acting on the book include gravity pushing up and friction pushing to the right, and these forces are balanced. So the correct option is C.

Explanation:

The force acting on a book sitting at rest on a table is gravity pushing down and the table pushing up with a normal force. Since the book is at rest, these forces must be equal in magnitude but opposite in direction, and therefore they are balanced. Option C, gravity pushing down and the table pushing up; balanced, is the correct answer. The force of gravity is also known as the book's weight, and since the book is not accelerating, the normal force must be equal to the gravitational force to maintain equilibrium, according to Newton's first law of motion.

A) The most important factor for solubility is temperature

We define the solubility of a substance in a solvent at a particular temperature

a) for solids the solubility increases with increase in temperature

b) for gas the solubility decreases with increase in temperature

So temperature will have huge effect on solubility of a saturated solution

B) the amount of extra time spent stirring the solution will hardly any effect or may have a very little effect. As stirring helps in solubility and if we have a saturated solution then it will not affect the solubility of the solution

C) The solubility is affected by the pressure on solvent

For gaseous solute the solubility is proportional to the pressure exerted on the solvent. More the pressure more the solubility.

D) the other solutes may affect the solubility as they may react with the solute or may interfere with the solute solvent interaction

Hence answer is "B"

Answer:

Na2O

Explanation:

Just took the quiz

Decreasing the volume of an equilibrium mixture by a factor of 3 will cause a corresponding increase in pressure. According to Le Châtelier's Principle, the system will adjust to reduce this increase in pressure by shifting the equilibrium to the side with fewer moles of gas. Therefore, the mole fraction of chlorine gas, χcl2, will decrease.

To understand how changes in conditions might affect the mole fraction of chlorine gas, χcl2, it's necessary to refer to Le Châtelier's principle, which states that a system in equilibrium will adjust so as to reduce any stress placed on it. The stress can be a change in pressure, volume, or concentration of reactants or products.

If you decrease the volume of the system by a factor of 3, the system will adjust to decrease the pressure by shifting the equilibrium to the side with fewer moles of gas. Given the reaction SbCl3 (g) + Cl2 (g) and knowing that chlorine molecules dissociate as per Cl2 (g) -> 2Cl(g), the system will respond to the increased pressure by shifting to the right to reduce the total number of gas molecules. This decrease of chlorine gas on the left side of the reaction will cause its mole fraction to decrease.

It is important to remember that changes shifting the equilibrium according to these process follow the rules defined by chemical equilibrium concepts and reaction quotient (Qc) values.

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