ACT Science : How to find synthesis of data in chemistry

Study concepts, example questions & explanations for ACT Science

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Example Question #783 : Act Science

The rate of a reversible chemical reaction depends on many factors, including concentrations of the reactants and products, temperature, and presence of enzymes called catalysts. In the forward reaction, two reactants combine to form one product. However, in a reverse reaction, the product is broken down into the two reactants.

 

In order for a forward reaction to occur, the reactants moving around in the test tube must physically interact with each other. The more often reactants interact with each other, the more produce is formed in the same amount of time. The speed at which reactants combine into products (the rate of the reaction) can be calculated by dividing the amount of a chemical produced in a reaction (often measured in moles) by the time it takes to produce that amount.

 

In order to determine the effects of reactant and product concentration, temperature, and presence of catalysts on the rate of a reaction, a scientist studied the following reaction:

 

 

The scientist varied the conditions of the experiment and measured the rate of the reaction. The results are outlined in Table 1. The units of concentration are moles per liter.

Table_1

In order to display the relationship between the number of moles of H+ and the rate of the reaction in Experiments 1 and 4, the scientist could:

Possible Answers:

Plot the number of moles of H+ against the rate of the formation of HCl

Plot the number of moles of H+ against the moles of Cl-

Plot the number of moles of H+ against the temperature

Plot the number of moles of H+ against the moles of acid convertase

Correct answer:

Plot the number of moles of H+ against the rate of the formation of HCl

Explanation:

The question asks us to determine the best way to show the relationship between the moles of a certain reactant, H+, and the rate of the reaction. The most logical way would be to plot the moles versus the rate, providing a line or bar graph that would show how the rate increased with increasing concentration of the reactant. The other plot set ups do not provide a clear way to show how increasing or decreasing the concentration of a reactant would change the rate.

Example Question #784 : Act Science

The rate of a reversible chemical reaction depends on many factors, including concentrations of the reactants and products, temperature, and presence of enzymes called catalysts. In the forward reaction, two reactants combine to form one product. However, in a reverse reaction, the product is broken down into the two reactants.

 

In order for a forward reaction to occur, the reactants moving around in the test tube must physically interact with each other. The more often reactants interact with each other, the more produce is formed in the same amount of time. The speed at which reactants combine into products (the rate of the reaction) can be calculated by dividing the amount of a chemical produced in a reaction (often measured in moles) by the time it takes to produce that amount.

 

In order to determine the effects of reactant and product concentration, temperature, and presence of catalysts on the rate of a reaction, a scientist studied the following reaction:

 

 

The scientist varied the conditions of the experiment and measured the rate of the reaction. The results are outlined in Table 1. The units of concentration are moles per liter.

 

Table_1

The effect of temperature on the rate of reaction is best demonstrated by comparing which two trials?

Possible Answers:

Trials 1 and 8

Trials 3 and 6

Trials 1 and 4

Trials 5 and 8

Correct answer:

Trials 1 and 8

Explanation:

In Table 1, Trials 1 and 8 have the same number of moles of H+, Cl-, and HCl. Additionally, neither trial contains acid convertase. However, in Trial 8, we can see that the temperature was doubled from that of Trial 1. Thus, Trials 1 and 8 show the relationahip between temperature and reaction rate most clearly.

Example Question #785 : Act Science

The rate of a reversible chemical reaction depends on many factors, including concentrations of the reactants and products, temperature, and presence of enzymes called catalysts. In the forward reaction, two reactants combine to form one product. However, in a reverse reaction, the product is broken down into the two reactants.

 

In order for a forward reaction to occur, the reactants moving around in the test tube must physically interact with each other. The more often reactants interact with each other, the more produce is formed in the same amount of time. The speed at which reactants combine into products (the rate of the reaction) can be calculated by dividing the amount of a chemical produced in a reaction (often measured in moles) by the time it takes to produce that amount.

 

In order to determine the effects of reactant and product concentration, temperature, and presence of catalysts on the rate of a reaction, a scientist studied the following reaction:

 

 

The scientist varied the conditions of the experiment and measured the rate of the reaction. The results are outlined in Table 1. The units of concentration are moles per liter.

Table_1

If a scientist desired to produce the most HCl possible in a reaction, the scientist could:

Possible Answers:

Remove acid convertase

Decrease the temperature

Increase the moles of HCl

Increase the moles of both H+ and Cl-

Correct answer:

Increase the moles of both H+ and Cl-

Explanation:

Using Table 1 as a guide, we can see that the rate of the reaction increases when H+ and Cl- are individually doubled over Trial 1. Thus, it is reasonable to conclude that simultaneously increasing the moles of each of these would further increase the rate. The remaining options all have effects opposite that of maximizing the rate of reaction.

Example Question #781 : Act Science

The rate of a reversible chemical reaction depends on many factors, including concentrations of the reactants and products, temperature, and presence of enzymes called catalysts. In the forward reaction, two reactants combine to form one product. However, in a reverse reaction, the product is broken down into the two reactants.

 

In order for a forward reaction to occur, the reactants moving around in the test tube must physically interact with each other. The more often reactants interact with each other, the more produce is formed in the same amount of time. The speed at which reactants combine into products (the rate of the reaction) can be calculated by dividing the amount of a chemical produced in a reaction (often measured in moles) by the time it takes to produce that amount.

 

In order to determine the effects of reactant and product concentration, temperature, and presence of catalysts on the rate of a reaction, a scientist studied the following reaction:

 

 

The scientist varied the conditions of the experiment and measured the rate of the reaction. The results are outlined in Table 1. The units of concentration are moles per liter.

Table_1

In Experiment 8, if the moles of H+ were doubled, the expected rate of the reaction would be:

Possible Answers:

<20

> 250

> 100

< 80

Correct answer:

> 100

Explanation:

This question asks us to consider what the effect of doubling the moles of H+ would be on the rate of the reaction. However, we must take into consideration that Experiment 8 has a doubled temperature, making the base rate 100. If we consider Experiments 1 and 4, we can see that doubling the H+ concentration doubles the rate. Thus, we could predict that the rate would be somewhere around 200. The only option that fits the predicted value is a rate > 100.

Example Question #787 : Act Science

The rate of a reversible chemical reaction depends on many factors, including concentrations of the reactants and products, temperature, and presence of enzymes called catalysts. In the forward reaction, two reactants combine to form one product. However, in a reverse reaction, the product is broken down into the two reactants.

 

In order for a forward reaction to occur, the reactants moving around in the test tube must physically interact with each other. The more often reactants interact with each other, the more produce is formed in the same amount of time. The speed at which reactants combine into products (the rate of the reaction) can be calculated by dividing the amount of a chemical produced in a reaction (often measured in moles) by the time it takes to produce that amount.

 

In order to determine the effects of reactant and product concentration, temperature, and presence of catalysts on the rate of a reaction, a scientist studied the following reaction:

 

 

The scientist varied the conditions of the experiment and measured the rate of the reaction. The results are outlined in Table 1. The units of concentration are moles per liter.

 

Table_1

The direction of the reaction most likely depends on:

Possible Answers:

The moles of H+

The moles of Cl-

The moles of HCl

Not enough information to determine

Correct answer:

Not enough information to determine

Explanation:

The passage and Table 1 only describe the rate of formation of HCl, not whether the reaction primarily forms HCl or whether HCl is broken down into H+ and Cl-. Unless the passage described in more detail how HCl was formed, we cannot assume that the direction of the reaction is solely dependent on one of the factors listed in the table. While we can see that the rate of the reaction slows down when more HCl is initially present at the start of the reaction, we do not know if the reaction rate becomes negative at some point (meaning that more HCl is being broken down than formed).

Example Question #1 : How To Find Synthesis Of Data In Chemistry

Both gases and liquids are considered to be fluids that have individual molecules that move around with kinetic and potential energy. Kinetic energy, defined as the energy related to motion, takes three forms: translational energy that occurs as a molecule moves from position A to position B, rotational energy that occurs as a molecule spins around an imaginary axis at its center of mass, and vibrational energy that occurs as individual atoms in a molecular bond move towards and away from each other. Usually, molecules possess varying combinations of kinetic energy forms. In contrast, potential energy is defined as stored energy that could be released to become kinetic energy. The total energy of a molecule is fixed, meaning that a molecule has some combination of kinetic and potential energies.

 

Varying amount of kinetic and potential energies define how molecules in a fluid interact with each other. For example, when the kinetic energy of a molecule is high (greater than 1000J), it can no longer interact with neighboring molecules strongly enough to remain a liquid. However, if the potential energies are too high (greater than 1000 J), molecules cannot escape a liquid to become a gas. If the kinetic energy is high and the potential energy is low, molecules tend to become a gas and can be modeled by an equation known as the Ideal Gas Law:

 

 

 

Where P is the pressure of a gas, V is the volume, n is the number of moles of a gas, R is a constant, and T is temperature in degrees Kelvin.

 

The Ideal Gas Law perfectly applies to particles with no mass, no intermolecular interactions, and no true volume. However, real molecules do not adhere perfectly to the Ideal Gas Law.

If the kinetic and potential energies of a liter of oxygen molecule are 1500 J and 100 J, respectfully, the liter is most likely to be in what phase according to the passage? 

Possible Answers:

Liquid

Solid

Cannot Be Determined

Gas

Correct answer:

Gas

Explanation:

According to the second paragraph of the passage, we learn that molecules that have high kinetic energy (defined as > 1000 J) and low potential energy (< 1000 J) are less likely to interact with each other to form the liquid or solid phase. Thus, this leaves the gas phase for these molecules to inhabit. 

Example Question #781 : Act Science

Both gases and liquids are considered to be fluids that have individual molecules that move around with kinetic and potential energy. Kinetic energy, defined as the energy related to motion, takes three forms: translational energy that occurs as a molecule moves from position A to position B, rotational energy that occurs as a molecule spins around an imaginary axis at its center of mass, and vibrational energy that occurs as individual atoms in a molecular bond move towards and away from each other. Usually, molecules possess varying combinations of kinetic energy forms. In contrast, potential energy is defined as stored energy that could be released to become kinetic energy. The total energy of a molecule is fixed, meaning that a molecule has some combination of kinetic and potential energies.

 

Varying amount of kinetic and potential energies define how molecules in a fluid interact with each other. For example, when the kinetic energy of a molecule is high (greater than 1000J), it can no longer interact with neighboring molecules strongly enough to remain a liquid. However, if the potential energies are too high (greater than 1000 J), molecules cannot escape a liquid to become a gas. If the kinetic energy is high and the potential energy is low, molecules tend to become a gas and can be modeled by an equation known as the Ideal Gas Law:

 

 

 

Where P is the pressure of a gas, V is the volume, n is the number of moles of a gas, R is a constant, and T is temperature in degrees Kelvin.

 

The Ideal Gas Law perfectly applies to particles with no mass, no intermolecular interactions, and no true volume. However, real molecules do not adhere perfectly to the Ideal Gas Law.

If the kinetic and potential energies of a liter of oxygen molecules are 250 J and 1200 J, respectfully, the liter is most likely to be in what phase according to the passage?

Possible Answers:

Liquid

Cannot Be Determined

Solid

Gas

Correct answer:

Liquid

Explanation:

According to the second paragraph of the passage, molecules that have low kinetic energy and high potential energy interact with each other to form the liquid phase. The passage implies that they do not have enough energy to prevent interaction with one another and thus interact to form a liquid. 

Example Question #1 : How To Find Synthesis Of Data In Chemistry

Both gases and liquids are considered to be fluids that have individual molecules that move around with kinetic and potential energy. Kinetic energy, defined as the energy related to motion, takes three forms: translational energy that occurs as a molecule moves from position A to position B, rotational energy that occurs as a molecule spins around an imaginary axis at its center of mass, and vibrational energy that occurs as individual atoms in a molecular bond move towards and away from each other. Usually, molecules possess varying combinations of kinetic energy forms. In contrast, potential energy is defined as stored energy that could be released to become kinetic energy. The total energy of a molecule is fixed, meaning that a molecule has some combination of kinetic and potential energies.

 

Varying amount of kinetic and potential energies define how molecules in a fluid interact with each other. For example, when the kinetic energy of a molecule is high (greater than 1000J), it can no longer interact with neighboring molecules strongly enough to remain a liquid. However, if the potential energies are too high (greater than 1000 J), molecules cannot escape a liquid to become a gas. If the kinetic energy is high and the potential energy is low, molecules tend to become a gas and can be modeled by an equation known as the Ideal Gas Law:

 

 

 

Where P is the pressure of a gas, V is the volume, n is the number of moles of a gas, R is a constant, and T is temperature in degrees Kelvin.

 

The Ideal Gas Law perfectly applies to particles with no mass, no intermolecular interactions, and no true volume. However, real molecules do not adhere perfectly to the Ideal Gas Law.

At a constant volume, the relationship between pressure and temperature as presented in the passage may best be depicted as:

Possible Answers:

Screen_shot_2014-03-08_at_7.53.32_am

Screen_shot_2014-03-08_at_7.53.20_am

Screen_shot_2014-03-08_at_7.53.26_am

Screen_shot_2014-03-08_at_7.53.38_am

Correct answer:

Screen_shot_2014-03-08_at_7.53.26_am

Explanation:

Using the provided formula, we see that if volume is held constant, the relationship between pressure and temperature is a direct relationship. We know this because both are in the numerator on their respective sides of the equals sign. Thus, as pressure increases, we would also expect temperature to increase. A positive, straight line serves as the guide for this relationship.

Example Question #1 : How To Find Synthesis Of Data In Chemistry

Both gases and liquids are considered to be fluids that have individual molecules that move around with kinetic and potential energy. Kinetic energy, defined as the energy related to motion, takes three forms: translational energy that occurs as a molecule moves from position A to position B, rotational energy that occurs as a molecule spins around an imaginary axis at its center of mass, and vibrational energy that occurs as individual atoms in a molecular bond move towards and away from each other. Usually, molecules possess varying combinations of kinetic energy forms. In contrast, potential energy is defined as stored energy that could be released to become kinetic energy. The total energy of a molecule is fixed, meaning that a molecule has some combination of kinetic and potential energies.

 

Varying amount of kinetic and potential energies define how molecules in a fluid interact with each other. For example, when the kinetic energy of a molecule is high (greater than 1000J), it can no longer interact with neighboring molecules strongly enough to remain a liquid. However, if the potential energies are too high (greater than 1000 J), molecules cannot escape a liquid to become a gas. If the kinetic energy is high and the potential energy is low, molecules tend to become a gas and can be modeled by an equation known as the Ideal Gas Law:

 

 

 

Where P is the pressure of a gas, V is the volume, n is the number of moles of a gas, R is a constant, and T is temperature in degrees Kelvin.

 

The Ideal Gas Law perfectly applies to particles with no mass, no intermolecular interactions, and no true volume. However, real molecules do not adhere perfectly to the Ideal Gas Law.

At a constant temperature, the relationship between pressure and volume is best illustrated as:

Possible Answers:

Screen_shot_2014-03-08_at_7.59.03_am


Screen_shot_2014-03-08_at_7.58.58_am

Screen_shot_2014-03-08_at_7.59.08_am

Screen_shot_2014-03-08_at_7.59.13_am

Correct answer:


Screen_shot_2014-03-08_at_7.58.58_am

Explanation:

Using the provided formula, we see that at a fixed temperature, pressure is inversely proportional to volume. They are on the same side of the equals sign, but can better be equated by rearranging the equation as: . We can now see more clearly that pressure is inversly proportional to volume. This inverse relationship is depicted as a negative sloped linear curve.

Example Question #2 : How To Find Synthesis Of Data In Chemistry

Chemists can model how solids, liquids, and gases behave at different temperatures and pressures with a graph called a phase diagram. When the pressure and temperature are simultaneously known, a scientist can predict whether the material will be in a specific state. The diagram is divided into sections depending on the phase and the lines between sections represent phase transitions occurring between two or more separate phases.

 

In general, solids of neatly stacked molecules exist when temperatures are low and pressures are intermediate. These values decrease the kinetic energy of the molecules enough to allow for attractive forces to begin the stacking process. Liquids, by contrast, are found at intermediate pressures and temperatures. The temperature is high enough to impart enough kinetic energy to prevent solid formation and the pressure is high enough to prevent the liquid from becoming a gas. Finally, a gas forms at low pressures and high temperatures. The high level of kinetic energy prevents molecules from associating with one another.

 

Materials can undergo processes called phase transitions, meaning they can transition from one phase to another. The transition from a solid to a liquid is called melting, while the reverse transition is called freezing. Vaporization occurs when a liquid becomes a gas, while condensation occurs when a gas becomes a liquid. Finally, in a process called sublimation, a solid can directly become a gas without passing through a liquid phase. Additionally, when a gas directly becomes a solid, this is known as deposition. 

Act_ps

The process as a substance goes from its phase in area one to its new phase in area two is called __________.

Possible Answers:

Melting

Condensation

Freezing

Vaporization

Correct answer:

Melting

Explanation:

Paragraphs two and three in the passage help us answer this question. Using the information contained in paragraph two, we are able to determine that area one corresponds to the solid phase (low temperature and intermediate pressure) and area two corresponds to the liquid phase (intermediate pressures and temperatures). Thus, we are transitioning between the solid and liquid phases. According to paragraph three, this process is called melting. 

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