A student added 5 grams of calcium chloride, a white solid substance, to 15 grams of water at 220 C. Several observations were made and the student inferred that a chemical reaction occurred.



Which observation best supports the student's inference that a chemical reaction occurred?

The gas pressure will change by a factor of 4 if the volume is doubled and the temperature is halved.

What is temperature?

Temperature is a measure of the average kinetic energy of the molecules in an object or system. It is a measure of the average amount of heat stored in a system. Temperature is a physical property and is typically expressed in units of Kelvin, Celsius, or Fahrenheit. Temperature can be measured using thermometers, which are devices that measure the degree of heat in the environment. Temperature is an important factor in many physical processes, such as the rate of chemical reactions and the speed of sound. It also affects the behavior of many materials, such as how metals expand and contract as they heat up and cool down. Temperature also influences many aspects of biology, including the life cycles of plants and animals. Temperature is an important indicator of climate and is used to monitor regional and global climate trends.

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the autoionization of water is represented by the equation above. Values of pkw at various temperatures are listed in the table below. Based on the information above, the statement that is true is "The autoionization of water increases with increasing temperature.

"This is because the values of Kw increase with increasing temperature, as seen in the table provided. Since Kw represents the autoionization of water, it can be concluded that the autoionization of water increases with increasing temperature.

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Answer:

B) It converts nitrogen into a form that humans can obtain by eating other organisms.

Answer:

electrolysis is the process by which electric current is passed through a substance to effect a chemical change.

Answer:

The production of a chemical reaction by passing an electric current through an electrolyte is called electrolysis. We know that an electrolyte contains ions, which are charged. The positively charged ions are called cations, because they are attracted to the cathode, and the negatively charged ones are called anions because they are attracted to the anode. We know that unlike charges attract and like charges repel. Cations, being positively charged, get attracted to the negatively charged cathode and move toward it. Anions, being negatively charged, get attracted to the positively charged anode and move toward it. This explains how ions move in an electrolytic cell, and thus ‘conduct’ an electric current. A chemical reaction takes place at the anode and the cathode. This can be observed as the formation of bubbles (due to the production of gases) or deposition of metal on the electrodes or a change in the color of the electrolyte. The reaction varies depending on the metals used for the electrodes and the electrolyte chosen. Electrolysis of a solution of sodium chloride (NaCl) produces hydrogen gas (H2), chlorine gas (Cl2), and sodium hydroxide (NaOFI).

The pictures of electrolysis examples are shown below:

Answer:

Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution

Answer:

* the total mass of the reactants must equal the total mass of the  

products (Law of Conservation of Mass)

Chemical Equation             something that uses formulas and symbols to  

  represent the relative amounts of the reactants  

  and products of a chemical reaction

Explanation:

Answer: When you add an electron to zinc, it needs some extra energy. This is because zinc atoms naturally don't like having an extra electron. The extra electron and the electrons already present in zinc repel each other due to their negative charges. So, you have to give some energy to the zinc atom to overcome this repulsion and make it accept the additional electron. Basically, energy input is required to make zinc accept an extra electron because the electron doesn't fit easily and needs some force to be added.

Explanation: hope this helps

Physical properties describe the characteristics of a substance that can be observed or measured without changing its composition, while chemical properties describe how a substance interacts with other substances to form new substances.

Physical properties include characteristics such as color, density, melting point, boiling point, and conductivity. These properties can be observed or measured without changing the substance's chemical composition. Chemical properties, on the other hand, describe the reactivity of a substance and how it interacts with other substances to form new substances.

Chemical properties are determined by the substance's molecular composition and can only be observed by testing the substance's reactivity. For example, flammability is a chemical property because it describes how a substance reacts with oxygen to form new substances, while density is a physical property because it can be observed without changing the substance's composition.

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(C.) ch3ch2ch2ch2ch2oh. The option C compound, ch3ch2ch2ch2ch2oh, contains the most -OH groups of the compounds listed, making it the most soluble in water.

The quantity of hydroxyl (-OH) groups a molecule has typically affects how soluble it is in water. The compound in option C, ch3ch2ch2ch2ch2oh, contains the most -OH groups out of all the alternatives, making it the most water soluble.

In comparison to option C, the other two, A and B, are less soluble in water because they contain fewer -OH groups in their molecular structure. Option D, which states that all of these chemicals are equally soluble in water, is false because the molecular structure of an alcohol affects how soluble it is in water, and not all alcohols have the same molecular structure.

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Answer:

HBr

Explanation:

Answer:

The answer is in fact HBr

Explanation:

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Answer:

The three main rock types are igneous, metamorphic and sedimentary. The three processes that change one rock to another are crystallization, metamorphism, and erosion and sedimentation. Any rock can transform into any other rock by passing through one or more of these processes. This creates the rock cycle.

John Dalton's main contribution to atomic theory was the idea that every element consisted of one type of atom. Option C is correct.

In the early 19th century, John Dalton proposed that all matter is made up of small, indivisible particles called atoms. He also suggested that atoms of the same element are identical in their physical and chemical properties, and that atoms of different elements combine in simple, whole-number ratios to form compounds.

While Dalton's atomic theory was not completely correct (for example, atoms can be divided into smaller parts, as in the case of subatomic particles), it was an important step in the development of modern atomic theory.

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The  two other parts of a vehicle that help keep passenger safe are;

Airbags is very useful in a lace where a collision occurs , a car's airbags will inflate to protect the driver and passengers from frequent contact locations, such as the steering wheel, dashboard, and sides of the car.

Seatbelts, often known as safety belts, are a type of restraint device that keeps occupants securely in place during an accident or sudden stop, lessening the force of the vehicle's interior on the body and avoiding ejection. Since they were initially developed, seatbelts have undergone tremendous development.

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Answer:

The velocity of the bb when it reaches a height of 203 m can be determined using the laws of projectile motion. Since the bb is moving vertically upwards, its velocity at that height will be zero.

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Answer: v = 83.96 m/s

Assuming the acceleration due to gravity is approximately 9.8 m/s^2, we can use the principles of projectile motion and energy conservation.

Using the equation for the vertical displacement of an object in free fall:

Δy = (v₀² - v²) / (2g)

Δy = vertical displacement (203m)

v₀ = initial velocity (105 m/s)

v = final velocity (not known yet)

g = accerlation due to gravity (9.8 m/s^2)

Lets rearrange the equation to solve for the final velocity:

v = v = √(v₀² - 2gΔy)

Substituting the given values:

v = √(105² - 2 * 9.8 * 203)

v ≈ √(11025 - 3979.6)

v ≈ √(7054.4)

v ≈ 83.96 m/s

Therefore, when the BB pellet is at the height of 203m, its velocity will be approximately 83.96 m/s.

Answer:

20.(45)L or about 20.4545L

Explanation:

PV = nRT

Where:

P - pressure

V - volume

n - number of particle moles

R - a constant

T - temperature in K

We can assume the P and n (and definitely R) stay the same, so we infer that

\(V_1 = \frac{nRT_1}{P} = 15L\\V_2 = \frac{nRT_2}{P}\\V_1 / V_2 = \frac{nRT_1}{P} / \frac{nRT_2}{P} = \frac{T_1}{T_2}\\\\15L / V_2 = \frac{330K}{450K} = \frac{11}{15}\\\\V_2 = 15L \cdot \frac{15}{11} = 20.(45)L\)

D. Able to answer for one's conduct and obligations

The amygdala is a pair of almond-shaped structures located in the brain's temporal lobes. It is part of the limbic system, which is involved in the processing of emotions and memory. The amygdala is involved in the formation of memories associated with emotional events, as well as the reaction to those memories.

The amygdala also plays a role in the regulation of the body's fight-or-flight response, which is the autonomic nervous system's response to danger or perceived danger. It is thought to be involved in the formation of fears and phobias, as well as the development of aggressive behaviors. In addition, the amygdala is believed to be involved in the processing of social cues, such as facial expressions and body language.

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To determine the moles of O₂ needed, we have to know in what ratio the two reactants react and then use the moles of C₂H₂  in reaction to determine the moles of O₂  needed. We can find this out based on their coefficient in a balanced equation:

Write a Balance Equation

2C₂H₂  +   5O₂   →     4CO₂   +   2H₂O

Compare the Mole Ratio (Equation Coefficient of C₂H₂  to  O₂)

Based on the equation, the mole ratio of C₂H₂  to  O₂  is 2 to 5. Therefore for every molecule of C₂H₂, ⁵/₂ C₂H₂ molecules are needed to react.

Find the moles of O₂

Since the number of moles of  C₂H₂   =    2.60 moles

                                then moles of O₂ = 2.60 moles × ⁵/₂

Answer:

3. C6H12O6 → 2CH3CH2OH + 2CO2

Explanation:

 In fermentation a catabolic process occurs, where an organic substance (C6H12O6) is transformed into a simpler one (CH3CH2OH), through incomplete oxidation, which does not require oxygen. Sugars are transformed into ethyl alcohol and carbon dioxide.

The equation C₆H₁₂O₆ → 2CH₃CH₂OH + 2CO₂ represents fermentation

Fermentation is an enzyme catalyzed, metabolic process whereby organisms convert starch or sugar to alcohol or an acid anaerobically releasing energy.

In this process a large molecule is broken down to a smaller molecule.

Among the Equations given Equation 3  

C₆H₁₂O₆ → 2CH₃CH₂OH + 2CO₂

represents fermentation due to two reasons

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The volume of hydrogen chloride gas, HCl at s.t.p yielded is determined as 4.032 dm³.

The number of moles of the gas yield is calculated as follows;

n = 1.2 dm³ x 0.15 mol/dm³

n = 0.18 mole

one mole of HCl gas at stp = 22.4 dm³

0.18 mole = ?

= 0.18 x 22.4 dm³

= 4.032 dm³

Thus, the volume of hydrogen chloride gas, HCl at s.t.p yielded is determined as 4.032 dm³.

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The molecular equation shows the overall chemical reaction, the complete ionic equation shows the species in their ionic form, and the net ionic equation shows only the species that participate in the reaction.

When calcium metal is added to hydrochloric acid solution, a reaction takes place and calcium chloride and hydrogen gas are produced. The chemical equation for this reaction is:
Ca (s) + 2HCl (aq) → CaCl₂ (aq) + H₂ (g)

The molecular equation shows all the reactants and products in their undissociated form:
Ca (s) + 2HCl (aq) → CaCl₂ (aq) + H₂ (g)

The complete ionic equation shows all the reactants and products in their ionic form, including the spectator ions:
Ca (s) + 2H⁺ (aq) + 2Cl⁻ (aq) → Ca²⁺ (aq) + 2Cl⁻ (aq) + H₂ (g)

The net ionic equation shows only the species that are involved in the chemical reaction, leaving out the spectator ions:
Ca (s) + 2H⁺ (aq) → Ca²⁺ (aq) + H₂ (g)

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Skeletal muscle was the Effector in the reaction time test and motor response reflects the muscular component of reaction time.

The Effector in the reaction time test was the skeletal muscle in the finger which is used to press the button. muscle and glands produces a specific response to a stimuli's and the motor response was reaction time test is the time between electromyographic activity and movement and the motor response is the response which reflects the skeletal muscle component of reaction time.

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To determine the number of moles of water produced in the given reaction 2C8H18(g) + 25O2(g) → 16CO2(g) + 18H2O(g), we need to compare the stoichiometric coefficients of water (H2O) with the other reactants and products. From the balanced equation, it can be concluded that 18 moles of water are produced for every 2 moles of C8H18 consumed.

The balanced equation shows that for every 2 moles of C8H18 consumed, 18 moles of H2O are produced. This ratio is obtained by comparing the stoichiometric coefficients of water and C8H18 in the balanced equation.

Therefore, if we have a known amount of C8H18 and want to determine the corresponding moles of water produced, we can use the ratio:

moles of H2O = (moles of C8H18) x (18 moles of H2O / 2 moles of C8H18)

The ratio of 18 moles of H2O to 2 moles of C8H18 indicates that for every 2 moles of C8H18, 18 moles of H2O are produced in the reaction.

Using this ratio, you can calculate the number of moles of water produced by multiplying the number of moles of C8H18 by the ratio of 18 moles of H2O to 2 moles of C8H18.

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Answer:

The answer is Aluminum

Hope this helps you

Answer:

The mass is 20, 89 grams of He.

Explanation:

We calculate the weight of 1 mol of He, from the atomic weight of each element obtained from the periodic table: Weight 1 mol He= 4, 0020602 g. 1 mol He-----4, 0020602 g. 5,22 mol He---x= (5,22 mol He x4, 0020602 g)/ 1 mol He= 20, 89 g

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The mass of 5.22 mol of He will be 20.84 grams.

We have 5.22 mol of He.

We have to calculate its Mass.

Helium is a chemical element with the symbol He and atomic number 2. It is a gas which is colorless, odorless, tasteless, non-toxic, inert and monatomic.

According to the question -

Number of moles of Helium = 5.22 mol

Now, I mole of Helium will have its mass equal to its Atomic weight. Therefore -

Mass of 1 mole of He = 4.002602 g

So, the mass of 5.2 mol of He will be = 5.2 x 4.002602 = 20.84 grams

Hence, the mass of 5.22 mol of He will be 20.84 grams.

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Answer:

The answer would be topaz

To prepare 10.0 ml of a 0.25% m/v HCl solution, you will need to mix 2.5 ml of 1% m/v HCl solution with 7.5 ml of distilled water.

To make 10.0 ml of a 0.25% m/v HCl solution from 1% m/v HCl, dilute the 1% m/v HCl solution by a factor of 4.

Here's how to figure out how much 1% m/v HCl and distilled water you'll need:

Determine the concentration of HCl in the final solution:

A 0.25% m/v HCl solution contains 0.25 grams of HCl per 100 mL. 

As a result, there will be 0.25 g/100 ml x 10 ml = 0.025 g of HCl in 10 ml of solution.

Determine the quantity of 1% m/v HCl required:

1% m/v HCl implies that there is one gram of HCl in every 100 ml of solution. You will need the following to make 0.025 g of HCl:

0.025 g/1 g x 100 ml = 2.5 ml of 1% m/v HCl solution

Determine the amount of distilled water required:

To prepare the remaining 7.5 ml of solution, use the following :

10 ml - 2.5 ml = 7.5 ml of distilled water

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Answer:

An element in Group 16 (oxygen, sulfur, selenium, etc.)

Explanation:

Sodium (Na) typically forms the cation Na⁺ during ionic bonding. If the overall charge of the compound is neutral (0), and there are two Na⁺ ions present (+1 + (+1) = +2), the element serving as the anion must have a -2 charge (+2 + (-2) = 0). Elements in group/column 16 have a -2 charge when ionized.

Answer:

no

Explanation: