Which of the following is a chemical change?
A. Water freezing to form ice
B. Sugar dissolves in water
C. Gasoline burns in a car engine
D. A piece of metal expands when it is heated

Answer:

pollution I think

Explanation:

Answer:

See attached image.

Explanation:

The explanations are on the attachment.  The numerical results are below.

1.  63g/7cm^3 = 9 g/cm^3

2.  The m or mm must be converted so that the units are the same.  1 m = 1000 mm.  I'll convert the meters to mm:  0.080 m = 80 mm.

480 mm^2/80 mm = 6 mm

3.  L times L makes no physical sense, unless this is a new Star Wars technique for making dark matter.  Entertaining, but useless.

Answer:

Mass = 1.217 g

Explanation:

Given data:

Mass of Sb₂O₃ = 1.50 g

Mass of Sb produced = ?

Solution:

Chemical equation:

Sb₂O₃ + 3C    →     2Sb + 3CO

Number of moles of Sb₂O₃:

Number of moles = mass/ molar mass

Number of moles = 1.50 g/ 291.49 g/mol

Number of moles = 0.005 mol

now we will compare the moles of Sb₂O₃ and Sb.

                   Sb₂O₃          :           Sb

                      1                :           2

                     0.005        :       2/1×0.005 = 0.01

Mass of Sb:

Mass = number of moles × molar mass

Mass = 0.01 mol × 121.76 g/mol

Mass = 1.217 g

Answer :The reason why compression is more difficult is a direct illustration of quantum mechanics.

Answer:

2.8 X 10-5s in standard notation is 28-5s

Explanation:

Multiply 2.8 by 10

The time needed to go from the original number of atoms to one-half of that number is the same as the time needed to go from one-half of the number of atoms to one-quarter of the number.

This is because the rate of radioactive decay is constant, meaning that the same amount of time is required for each successive halving. The time required to get from the original number of atoms to half that number is the same as the time required to go from half the original number of atoms to quarter of that number. The duration it takes for half of an element's parent isotopes to transform into daughter isotopes is known as its half life. While only one electron is lost during beta decay, the nucleus loses two protons and two neutrons during alpha decay. Radiation decay occurs exponentially.

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Answer:

C6H12O6

Explanation:

Molar mass of empirical formula:

12.01+2*1.008+16=30.026

Divide molar mass of molecular formula by 30.026

180/30=~6

Scale up the empirical formula by a factor of 6.

C6H12O2 (glucose)

Answer:

C6H12O2

Explanation:

Scale up the empirical formula by a factor of 6.

C6H12O2 (glucose)

To determine the amount of chlorine required to produce 65 grams of sodium chloride (NaCl) in the reaction 2Na + Cl₂ → 2NaCl, we need to consider the stoichiometry of the reaction. Therefore, approximately 39.53 grams of chlorine are required to produce 65 grams of NaCl.

The balanced equation tells us that for every 1 mole of Cl₂, we obtain 2 moles of NaCl.First, we calculate the molar mass of NaCl:

Na: 22.99 g/mol

Cl: 35.45 g/mol

Molar mass of NaCl: 22.99 + 35.45 = 58.44 g/mol

Now, we can calculate the number of moles of NaCl:

65 g of NaCl / 58.44 g/mol = 1.114 mol of NaCl

Since the reaction ratio is 1 mole of Cl₂ to 2 moles of NaCl, we need half the amount in moles:

1.114 mol of NaCl / 2 = 0.557 mol of Cl₂

Finally, we calculate the mass of chlorine needed using its molar mass:

0.557 mol of Cl₂ × 70.90 g/mol = 39.53 g of chlorine

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The pOH of the 0.742 M solution of a weak base is 3.69. The pH of the 0.742 M solution of a weak base is 10.31.

We can use the equilibrium expression for the dissociation of the weak base B to find the concentration of hydroxide ions in the solution: B + H₂O ⇌ BH+ + OH-

Kb = [BH+][OH-]/[B]

Since we are given that the initial concentration of B is 0.742 M, we can assume that the concentration of B remains essentially unchanged during the dissociation process. Therefore, we can simplify the expression for Kb as follows:

Kb ≈ [OH-]^2/0.742

Solving for [OH-], we get:

[OH-] ≈ \(\sqrt{Kb x [wake bas]}\)

[OH-] ≈ \(\sqrt{4.45 × 10^-7 x 0.742}\)

[OH-] ≈ 2.03 × 10⁻⁴ M

The concentration of OH- ions are 2.03 × 10⁻⁴ M, so the pOH can be calculated using the equation:

pOH = -log[OH-]

pOH = -log(2.03 • 10-4)

pOH = 3.69

The pH can then be calculated using the relationship between pH and pOH:

pH + pOH = 14

pH = 14 - pOH

pH = 14 - 3.69

pH = 10.31

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The maximum number of amino acid side chains that can potentially form an ionic bond with the side chain of His depends on the pH value.

To determine the maximum number of amino acid side chains that can potentially form an ionic bond with the side chain of His at different pH values, we need to consider the ionization state of the side chains involved.

At different pH values, the ionization state of amino acid side chains can change. In this case, we are interested in the side chain of His (histidine) and its ability to form an ionic bond with other side chains.

The side chain of His has a pKa value of approximately 6.0. At pH values below its pKa, the His side chain is mostly protonated and carries a positive charge. At pH values above its pKa, the His side chain is mostly deprotonated and carries a neutral charge.

Let's calculate the maximum number of amino acid side chains that can potentially form an ionic bond with the side chain of His at different pH values:

At pH 2.1:

At pH 2.1, the side chain of His is mostly protonated and carries a positive charge. It can potentially form an ionic bond with negatively charged side chains. Assuming all other side chains are negatively charged, the maximum number would be determined by the number of amino acids with negatively charged side chains in the protein sequence.

At pH 7:

At pH 7, the side chain of His is close to its pKa value. It is partially protonated and partially deprotonated. The exact charge distribution depends on the specific pH and the pKa values of other amino acid side chains present in the protein sequence.

At pH 11.5:

At pH 11.5, the side chain of His is mostly deprotonated and carries a neutral charge. It cannot form ionic bonds with other side chains.

At pH 13.5:

At pH 13.5, the side chain of His is still mostly deprotonated and carries a neutral charge. It cannot form ionic bonds with other side chains.

The maximum number of amino acid side chains that can potentially form an ionic bond with the side chain of His depends on the pH value. At pH 2.1, the exact number would depend on the number of amino acids with negatively charged side chains in the protein sequence. At pH 7, the charge distribution is variable and depends on the specific pH and pKa values of other amino acid side chains. At pH 11.5, and pH 13.5, the side chain of His is mostly deprotonated and cannot form ionic bonds.

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Answer:

H2O

Explanation:

EASIEST FORMULA ON EARTH

Extrusion is the feature form at Earth's surface from the cooling of lava.

They are the ones that originate from a sudden cooling of the incandescent magma when it comes to the surface, which means that there is no time for crystals to form, either partially or totally.

Therefore, we can conclude that typical volcanic rocks are formed by the rapid cooling of lava and pyroclastic fragments.

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Answer:

A.

Explanation:

Answer:

There are 126 neutrons in the bismuth atom.

Explanation:

We are given that a Bi atom has an atomic mass of 209 amu and an atomic number of 83.

We want to find how many neutrons the bismuth atom has.

The atomic mass of an atom is equal to the mass of the protons + mass of neutrons (n.b. the electrons are part of the mass too, however they are very, very small. Therefore, we tend to count the mass of the electrons as 0 when calculating the atomic mass).

Recall that protons and neutrons both have a mass of about 1 amu.

Also recall that the proton number is also the atomic number. Because of this, the bismuth atom has 83 protons. And since that protons have a mass of about 1 amu, the atomic mass of the protons will be:

83 protons × \(\frac{1 amu}{1 proton}\) = 83 amu

That means that if the atomic mass is 209 amu, it is equal to the proton mass (83 amu) + an unknown mass of neutrons (let's say it is x amu).

As an equation, it will be:

83 + x = 209

Subtract 83 from both sides.

x = 126

This means that the neutrons will weigh 126 amu.

Since every neutron is about 1 amu, the amount of neutrons will be:

126 amu × \(\frac{1 neutron}{1 amu}\) = 126 neutrons

Answer:

126

Explanation:

To calculate for neutron #, subtract atomic # from atomic mass.

t hus 09- 83= 126

The volume of Object 2 can be determined from the water displacement data by subtracting the initial volume of the water (120.0 mL) from the final volume after the sphere is added (135.8 mL). This gives us a difference of 15.8 mL, which is the volume of Object 2.

The chemical explanation for this procedure is that the volume of Object 2 is calculated by subtracting the initial volume of water from the final volume of water after the object is added. This is due to the fact that the volume of the object displaces the water, and so the amount of water displaced is equal to the volume of the object.

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Answer:

H₂O₂

Explanation:

Hydrogen peroxide is a typical example of a compound molecule. A compound is made up of one or more atoms that are combined together in a definite grouping.

The properties of a compound is different from those of the elements that combines to from them.

Answer:

a. CH4 + 2O2 = CO2 + 2H2O

b. 2CH4 + 3O2 = 2CO + 4H2O

If wind blows over uneven land it becomes Gusty. The correct option to this question is D.

When wind blows over uneven land, it interacts with the various features and obstacles on the terrain, such as hills, valleys, and buildings.

This interaction causes the wind to change its direction and speed, leading to gusty conditions. Gusty winds are characterized by sudden, brief increases in wind speed, followed by a period of relatively calmer wind.

In addition to creating gusty winds, uneven terrain can also affect other aspects of wind behavior. For example, wind can be funneled through valleys or become blocked by hills and mountains, leading to localized variations in wind patterns. Additionally, the surface roughness of the terrain can influence the wind's overall speed and strength. However, the primary effect of uneven terrain on wind is the development of gusty conditions.

Wind blowing over uneven land becomes gusty due to its interaction with the various features and obstacles on the terrain. This leads to sudden changes in wind speed and direction, creating gusty winds.

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In the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.

Bicarbonate is an excellent buffering system because this compound can bind free hydrogen ions (H+) and thus the system avoids sudden changes in the pH of a solution.

In conclusion, in the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.

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Answer: any non-living thing

Explanation: abiotic means non-living

The Abiotic observation that the ecologist would record are ;

Abiotic factors in ecosystem are the non-living factors that play an essential role in determining how an ecosystem is different from other ecosystems. Some of the Abiotic factors that will distinguish ecosystems in the rainforest biome include ;

Hence we can conclude that The Abiotic factors/observation that the ecologist would record are ; Soil type, Climate , Precipitation and Sunlight

The options to your question are missing hence a general answer is provided above

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Answer:

Lead

Explanation:

Lower the specific heat faster it will heat, meaning liquid will heat up slowly than any other material mentioned above. Thus lead will heat up faster

The maximum safe operating temperature the engineer should recommend for this reaction is approximately 1063.77 degrees Celsius.

To calculate the maximum safe operating temperature, we need to consider the dimensions of the vessel, the maximum safe pressure, and the amount of gas inside.

First, let's convert the dimensions of the vessel from centimeters to meters:

Width = 48.0 cm = 0.48 m

Height = 57.6 cm = 0.576 m

Next, we need to calculate the volume of the vessel:

Volume = π * (radius)^2 * height

The radius of the vessel can be calculated as half of the width:

Radius = 0.48 m / 2 = 0.24 m

Volume = π * (0.24 m)^2 * 0.576 m

Volume ≈ 0.099 m^3

Now, we can use the ideal gas law to determine the maximum safe operating temperature. The ideal gas law is given by:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.

Rearranging the equation to solve for T:

T = (PV) / (nR)

To calculate the number of moles, we can use the molar mass of carbon dioxide (CO2):

Molar mass of CO2 = 12.01 g/mol (for carbon) + 2 * 16.00 g/mol (for oxygen)

Molar mass of CO2 ≈ 44.01 g/mol

Converting the mass of carbon dioxide from kilograms to grams:

Mass of CO2 = 2.45 kg * 1000 g/kg

Mass of CO2 = 2450 g

Now, we can calculate the number of moles:

Number of moles = Mass of CO2 / Molar mass of CO2

Number of moles = 2450 g / 44.01 g/mol

Number of moles ≈ 55.67 mol

The gas constant R is approximately 8.314 J/(mol·K).

Now, we can substitute the values into the equation:

T = (3.40 MPa * 0.099 m^3) / (55.67 mol * 8.314 J/(mol·K))

T ≈ 1063.77 K

Converting from Kelvin to Celsius:

T ≈ 1063.77 °C

The maximum safe operating temperature that the engineer should recommend for this reaction is approximately 1063.77 degrees Celsius.

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Answer:

A

Explanation:

A compound machine is a combination of two or more simple machines.

Answer:

Explanation:

4 min 15sec=255 seconds but idk what you actually want me to say what it is equal to as you haven't given anything to compare it to

A stiff metal bottle containing helium floats at the surface of the pond. If additional helium is added to that bottle, leaving its temperature and volume unchanged, the bottle will float because of the Archimedes principle.
This principle states that the buoyant force on a body is equal to the weight of the fluid displaced by the body. When a body is placed in a fluid, it experiences an upward force known as the buoyant force. If the buoyant force is greater than the weight of the body, the body will float.
In this case, the bottle containing helium floats on the surface of the pond because helium is less dense than air. Adding additional helium to the bottle will increase the volume of helium inside the bottle, but the temperature and volume of the bottle will remain the same. As a result, the buoyant force acting on the bottle will increase, making it float more easily on the surface of the pond.
However, it should be noted that the buoyant force acting on the bottle is also affected by the density of the fluid. If the density of the pond water increases, the buoyant force acting on the bottle will decrease, making it more difficult for the bottle to float. Therefore, the buoyancy of the bottle is determined by both the density of the fluid and the amount of helium in the bottle.

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In contrast to low-level radioactive waste, most high-level radioactive waste is currently stored temporarily on-site at nuclear power plants, or at specialized facilities.

High-level radioactive waste, a byproduct of both the nuclear power industry and nuclear weapons production, represents a daunting challenge in terms of public safety and environmental protection due to its highly radioactive nature and long half-life.

Unlike low-level radioactive waste which can be managed through more traditional means, the handling of high-level waste necessitates a temporary storage solution.

Currently located on-site at nuclear power plants or at specially designed facilities, until a permanent disposal solution can be developed and executed.

This tempestuous issue demands a delicate balance between safety, environmental preservation, and public opinion, as the ultimate aim is to secure a permanent disposal methodology that guarantees the safe containment and isolation of hazardous waste for eons to come.

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One 250ml beaker, a ph probe, 15ml of hcl, 15ml of Naoh, Various substances for pH measurement and 60ml of water are required to determine the ph of different substances.

To determine the pH of different substances, the following materials and steps are required:

Materials:

1. One 250ml beaker

2. pH probe or pH meter

3. 15ml of hydrochloric acid (HCl)

4. 15ml of sodium hydroxide (NaOH)

5. Various substances for pH measurement

6. 60ml of water

Procedure to measure the pH:

1. Start by filling the 250ml beaker with 60ml of water.

2. Immerse the pH probe or pH meter into the beaker, ensuring that it is properly calibrated according to the manufacturer's instructions.

3. Measure 15 ml of hydrochloric acid (HCl) using a graduated cylinder and add it to the beaker.

4. Measure 15 ml of sodium hydroxide (NaOH) using a graduated cylinder and add it to the beaker.

5. Stir the mixture gently to ensure proper mixing of the substances.

6. Take a sample of the substance whose pH needs to be determined and add it to the beaker.

7. Observe the pH reading on the pH probe or pH meter display.

8. Rinse the pH probe or pH meter with distilled water between measurements to avoid contamination.

9. Repeat the steps for each substance to obtain its respective pH value.

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Answer:

Powering society: Energy is essential for powering homes, businesses, industries, and transportation systems. It enables the functioning of modern society by providing electricity, heating, cooling, and mechanical power.

Economic growth: Reliable and affordable energy sources contribute to economic growth and development. Industries rely on energy to manufacture products, operate machinery, and provide services. Access to energy supports job creation, increases productivity, and drives economic competitiveness.

Improved quality of life: Energy plays a crucial role in improving the quality of life for individuals and communities. It enables access to clean water, sanitation, healthcare services, education, and information technology. Energy-powered devices and appliances enhance comfort, convenience, and entertainment.

Sustainable development: Renewable energy sources such as solar, wind, hydro, and geothermal offer advantages in terms of environmental sustainability. They help reduce greenhouse gas emissions, mitigate climate change, and decrease dependence on finite fossil fuel resources. Renewable energy also promotes energy diversification and enhances energy security.

Innovation and technology: The energy sector drives innovation and technological advancements. Research and development in energy technologies lead to more efficient, cost-effective, and environmentally friendly solutions. Advancements in energy storage, grid infrastructure, and smart systems contribute to a more resilient and flexible energy supply.

Environmental benefits: Transitioning to cleaner energy sources helps mitigate environmental issues. Renewable energy generation produces minimal air and water pollution, reducing the negative impact on ecosystems and human health. Decreased reliance on fossil fuels reduces carbon dioxide emissions, combating climate change.

Energy independence: Diversifying energy sources and reducing dependence on imports enhances energy security for countries. By developing domestic energy resources and investing in renewable energy, nations can reduce vulnerability to price fluctuations, geopolitical tensions, and supply disruptions.

Rural electrification: Energy access is crucial for rural areas where many people lack electricity. Reliable energy supply promotes economic opportunities, improves healthcare and education services, and enhances overall living conditions in rural communities.