Big points and Brainliest to the first correct answer.

Which best describes an element?
A.) a pure substance
B.) a type of a mixture
C.) a pure compound
D.) an impure substance

Answer: The molecules in hot water move faster and are slightly further apart.

Explanation:

There's more space between the molecules, the volume of hot water has fewer molecules in it and weighs a little bit less than the same volume of cold water. So hot water is less dense than cold water.

Answer:

either bacterial cells or plant cells but I think bacterial

Explanation:

from google: Bacteria are single celled microbes. Bacteria are classified into five groups according to their basic shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes). ... They can exist as single cells, in pairs, chains or clusters.

- cannot be human or mouse cells as both are animals and animal cells do not have cell walls

Answer:

I just looked up the types of matter energy has.

Explanation:

I believe the answer is D.

Sally's list of matter that have energy is not complete as all the types of matter have energy as all matter have mass , and mass and energy are related, so she should have added gases and solids to her list.

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of the  same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.

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Among the given options, the tests that are left-tailed are H0:μ≥18, Ha:μ<18, H0:μ≥11.3, Ha:μ<11.3, and H0:μ≥3.7, Ha:μ<3.7.

In these tests, the null hypothesis (H0) states that the population mean (μ) is greater than or equal to a specific value, while the alternative hypothesis (Ha) suggests that the population mean is less than that value.

A left-tailed test is used when the alternative hypothesis suggests that the population parameter is less than a certain value.

This indicates a left-tailed test, where the critical region is in the left tail of the distribution. These tests focus on detecting a significant decrease or difference in the population mean.

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Complete question :

Which of the hypothesis tests listed below is a left-tailed test? Select all correct answers.

Select all that apply: H0:μ≥18, Ha:μ<18 H0:μ≤19.3, Ha:μ>19.3 H0:μ=8, Ha:μ≠8 H0:μ≥11.3, Ha:μ<11.3 H0:μ≥3.7, Ha:μ<3.7

Answer:

Homeostasis is the answer

Explanation: it maintains a constant and stable environment

The bond energy is the energy that must be supplied to break the bond. Ionic substances are held together by strong bonds.

This question is incomplete but I will try to explain what is meant by average bond energy as the tables are missing.

The average bond energy of a bond simply means the energy that is stored in that bond as it holds two atoms together. It is equal to the energy that must be supplied to break the bond. The numerical value of the bond energy can not be deduced as the data is missing.

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Answer:

1. four in the first energy level, four in the second energy level

2. eight in the first energy level, zero in the second energy level

3. zero in the first energy level, eight in the second energy level

4. two in the first energy level, six in the second energy level *

Explanation:

1. four in the first energy level, four in the second energy level

2. eight in the first energy level, zero in the second energy level

3. zero in the first energy level, eight in the second energy level

4. two in the first energy level, six in the second energy level *

The mixture of **1.0 M \(Na_2CO_3\)**2 will have the lowest freezing point.

what is The freezing point of a substance?

The temperature at which a liquid transforms into a solid when cooled is known as the freezing point. It is often referred to as the temperature at which a solid melts.

A substance's freezing point is a collective attribute. This indicates that it is dependent on the number of drugs in the system.

The freezing point is given by; T - Ta = K * m * i

Where;

T = freezing point of the pure solution

Ta = freezing point of the solution containing the solute

K = freezing point constant

m = molality of the solution

i= Van't Hoff factor

If we look at all the options provided, KI has only two particles in the solution and a molality of 1.0 m hence it should exhibit the lowest freezing point of the solution.

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Two specific air pollutants that contribute to acid rain are sulfur dioxide (SO2) and nitrogen oxides (NOx).

Sulfur dioxide is primarily emitted from industrial processes such as the burning of coal and oil in power plants. One remediation strategy for SO2 is the installation of scrubbers in industrial facilities. Scrubbers remove SO2 from the emissions before they are released into the atmosphere.

Nitrogen oxides are primarily emitted from the combustion of fossil fuels in cars, trucks, and other vehicles. One remediation strategy for NOx is the use of catalytic converters in vehicles. Catalytic converters convert NOx into less harmful gases before they are released into the atmosphere.

Both of these remediation strategies can help reduce the amount of these pollutants in the air and, in turn, reduce the occurrence of acid rain.

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Answer:

Acids and bases aqueous solutions will conduct electricity because they contain dissolved ions. Therefore acids and bases are electrolytes. strong acids and bases will be electrolytes. weak acids and bases will be weak electrolytes.

Answer:

When weather conditions are ideal, some ferns, algae, moss,and even fungi, release spores into the air, often carried by the wind, by insects or birds until they land. Spores contain both male and female reproductive organs, which allows these plants to replicate themselves in a form of cloning.

Explanation:

The pH change can be determined by calculating the new pH of the buffer solution using the Henderson-Hasselbalch equation, which relates the pH of a buffer to the pKa of the weak acid and the ratio of its conjugate base (Y-) to the weak acid (HY).

pH = pKa + log ([Y-] final / [HY] final)

To calculate the pH change after adding Ba(OH)2 to the buffer solution, we need to consider the reaction between Ba(OH)2 and the weak acid (HY) in the buffer.

Ba(OH)2 reacts with HY to form BaY2 and water (H2O). Since BaY2 is a salt, it will dissociate in water to form Y- ions. This will affect the concentration of Y- in the buffer solution, and consequently, the pH.

First, we calculate the moles of Y- in the initial buffer solution:

moles of Y- = (0.140 M)(0.240 L) = 0.0336 mol

Next, we determine the change in moles of Y- after adding 0.0015 mol of Ba(OH)2:

change in moles of Y- = 0.0015 mol

The total moles of Y- in the solution after the reaction will be:

total moles of Y- = moles of Y- in initial solution + change in moles of Y-

total moles of Y- = 0.0336 mol + 0.0015 mol = 0.0351 mol

Finally, we can calculate the new concentration of Y-:

new concentration of Y- = total moles of Y- / volume of solution

new concentration of Y- = 0.0351 mol / 0.240 L = 0.146 M

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Answer:

In order to determine whether the original material was a uniform/pure-looking mixture or a chemical compound broken into two new compounds, the following points must be noted;

1. If the two new materials are separated by physical means without any  chemical change occurring, the original material is a pure-looking mixture, but if a chemical reaction was involved in separating the material, then it is a compound.

2. If the individual properties of properties of the constituents were retained in the original material, the substance is a mixture, but if the properties of the constituents differed entirely from that of the material, then the material is a compound.

3. If the constituents of the material are not present in a fixed ratio, the material is a mixture but if they are present in a fixed ratio, the material is a compound.

Explanation:

When a substance is being separated into its components, the nature of the substance can be determined by the components obtained.

Matter can be classified into pure substances and mixtures.

Pure substances include elements and compounds which have distinct chemical properties, whereas mixture are composed of two or more constituents physically joined together.

In order to determine whether the original material was a uniform/pure-looking mixture or a chemical compound broken into two new compounds, the following points must be noted;

1. If the two new materials are separated by physical means without any  chemical change occurring, the original material is a pure-looking mixture, if the a chemical reaction was involved in separating the material, then it is a compound.

For example, a sugar and water mixture can be easily separated by evaporation and crystallization to obtain sugar and water respectively, but water which is composed of the elements hydrogen and oxygen cannot be separated by any physical means but by means of a chemical reaction, electrolysis.

2. If the individual properties of properties of the constituents were retained in the original material, the substance is a mixture, but if the properties of the constituents differed entirely from that of the material, then the material is a compound.

For example, a pure-looking mixture of sugar and water has the sweet taste of sugar and the liquid properties of water. However, water, a compound composed of hydrogen and oxygen which are gases, is a liquid and gas properties entirely different from either two.

3. If the constituents of the material are not present in a fixed ratio, the material is a mixture but if they are present in a fixed ratio, the material is a compound.

For example, sugar and water can be mixed together in any ratio to produce a sugar solution, but hydrogen and oxygen are always in a fixed ratio of 2:1 in water

Answer:

Normally, it explains that matter cannot be created or destroyed. It demonstrates different chemical reactions that help show the different transformations of the matter but will never destroy it or create it.

Answer:

Explanation:

A neutral titanium atom will have 22 electrons. Therefore, its electron configuration will be 1s2 2s2 2p6 3s2 3p6 4s2 3d2.

Answer:  Write down the chemical equation first;

2H2 + O2 —-> 2H2O

2. Since the mass is given, use it to calculate the mole for each reactant;

mole = mass / molar mass

mole of H2 : 8/2 = 4 mole

mole of O2 : 30/16(2) = 0.9375 mole

Now, if you're not sure which reactant to use to calculate the mass of H2O using ratio since both answer are different, find the limiting reactant.

From the equation;

2 mol of H2 -> 2 mol of H2O

4 mol of H2 -> (4*2)/2 = 4 mol of H20

______________________________________

1 mol of O2 -> 2 mol of H2O

0.9375 mol of O2 -> (0.9375*2)/1 = 1.875 mol of H2O

Let's take a look at both numbers. Since H2 produces more water than O2, O2 will be the limiting reactant as it has the least mole of H2O. So now we are going to use O2 as our limiting reactant. Use the formula to calculate mass of water using mole.

mass of H2O : 1.875*(16+2) = 33.75 g

Thats it. Correct me if im wrong

Explanation:

CaBr2 is an ionic bond. This is because the calcium gives up an electron to each of the chlorine atoms resulting in the calcium becoming Ca2+ ions...

HClO3 is the stronger Brønsted-Lowry acid between the two compounds.

In the Brønsted-Lowry acid-base theory, an acid is defined as a substance that donates a proton (H+) and a base is a substance that accepts a proton. To determine which of the two acids, HClO3 or HClO2, is stronger, we need to assess their ability to donate a proton.

HClO3, also known as chloric acid, has a central chlorine atom bonded to three oxygen atoms and one hydrogen atom. The presence of three electronegative oxygen atoms surrounding the central chlorine atom increases the acidity of HClO3. The oxygen atoms withdraw electron density from the chlorine atom, making it more willing to donate a proton, thus making HClO3 a stronger acid.

HClO2, also known as chlorous acid, has a similar structure with a central chlorine atom bonded to two oxygen atoms and one hydrogen atom. Compared to HClO3, HClO2 has fewer electronegative oxygen atoms surrounding the central chlorine atom. This reduced electron withdrawal decreases the acidity of HClO2, making it a weaker acid compared to HClO3.

Therefore, HClO3 is the stronger Brønsted-Lowry acid between the two compounds.

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Answer:

I'm sorry, but I cannot see the observations or the data table you mentioned in your question. However, I can still provide you with some general guidance on how to approach the calculations and answer the questions based on the given information.

4. To calculate the concentration of the NaOH solution, you need to know the mass of NaOH used and the volume of the solution. The formula to calculate concentration is:

Concentration (in mol/L) = (Mass of NaOH (in grams) / molar mass of NaOH) / Volume of solution (in L)

Make sure to convert the mass of NaOH to moles by dividing it by the molar mass of NaOH. The molar mass of NaOH is the sum of the atomic masses of sodium (Na), oxygen (O), and hydrogen (H).

5. The balanced equation for the neutralization reaction between NaOH and HCl is:

NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

(aq) represents an aqueous solution, and (l) represents a liquid.

6a. To calculate the average concentration of HCl in the sample from site B, you need to know the volumes and concentrations of the NaOH and HCl solutions used in the titration. Use the formula:

Concentration of HCl (in mol/L) = (Volume of NaOH solution (in L) * Concentration of NaOH (in mol/L)) / Volume of HCl solution (in L)

Multiply the volume of NaOH solution used by its concentration to find the amount of NaOH used. Then, divide this amount by the volume of HCl solution used to find the concentration of HCl.

6b. To determine the pH of the water at site B, you need to know the concentration of HCl from the previous calculation. The pH can be calculated using the formula:

pH = -log10[H+]

Since HCl is a strong acid, it dissociates completely into H+ ions. Therefore, the concentration of H+ ions is equal to the concentration of HCl. Take the negative logarithm (base 10) of the H+ concentration to find the pH.

To check if the water is safe, compare the calculated pH value to the range provided (pH 4.5-7.5). If the pH falls within this range, the water is considered safe for plant and animal reproduction in an aquatic environment.

6c. Use a similar calculation as in 6a to determine the average concentration of HCl in the sample from site C.

6d. Use the concentration of HCl from 6c to calculate the pH using the formula in 6b. Follow the same procedure to check if the water is safe based on the pH range.

7. To find the most current pH value for the Grand River, you can search for the latest data from reliable sources such as environmental agencies, research institutions, or government websites. Compare this pH value to the pH values obtained in the experiment to assess the difference between them.

Remember, without the specific data and observations, the calculations and comparisons provided here are only general guidelines. It's important to use the actual data from your experiment to obtain accurate results and conclusions.

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Water 3.0 deals mainly with sewage treatment. The primary aim of this project is to reduce the harmful impacts of chemical pollutants from industrial and agricultural activities on natural water resources.

Currently, used wastewater treatment technologies can break down some of the chemicals in wastewater but not all of them. Chemicals that are not broken down are referred to as persistent organic pollutants. These chemicals persist in the environment for long periods, and they can cause severe damage to aquatic life and human health.
Currently, the primary challenge facing water treatment technologies is the removal of persistent organic pollutants such as pesticides, pharmaceuticals, and endocrine-disrupting chemicals from wastewater.

These pollutants are generally water-soluble and resist microbial degradation, making them hard to remove from wastewater using current water treatment technologies. For example, conventional activated sludge treatment used in wastewater treatment plants does not remove some persistent organic pollutants from wastewater.
Failure to remove these pollutants from wastewater can have significant environmental and health impacts.

For example, pharmaceutical chemicals can cause antibiotic resistance, while endocrine-disrupting chemicals can cause birth defects, cancer, and other health problems.

Therefore, there is a need to improve wastewater treatment technologies to remove persistent organic pollutants from wastewater.
In conclusion, wastewater treatment technologies can break down some chemicals but not all. Chemicals that are not broken down are persistent organic pollutants and pose a significant risk to the environment and human health. Therefore, it is important to develop wastewater treatment technologies that can remove these pollutants from wastewater.

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False.

Radiation itself does not typically have a green glow, intense heat, crackling sound, or ammonia smell. These descriptions do not accurately represent the properties of radiation.

The emission of energy in the form of particles or electromagnetic waves is referred to as radiation. Our senses cannot immediately notice it. Radiation is measured and detected using specialized apparatus and detectors.

Alpha particles, beta particles, gamma rays, and X-rays are a few examples of different forms of radiation that have unique characteristics and may be identified with the right tools. For instance, ionizing radiation is typically detected using Geiger-Muller counters or scintillation detectors, whereas radiation exposure is measured using dosimeters.

For precise radiation risk identification and protection, it's crucial to rely on the right detection tools and follow safety procedures.

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To prepare 1 L of a 0.0400 M anserine buffered solution with a pH of 7.20, we can first calculate the isoelectric point (pI) of anserine.

Next, we need to determine the desired pH and the starting pH of the solution. The starting pH of the 0.200 M anserine solution at its pI is 7.00, and the desired pH is 7.20.

We can use the formula for the buffer capacity,

Buffer capacity = (base concentration) / (acid concentration)

The buffer capacity of the anserine solution is:

Buffer capacity = (0.200 M) / (0.300 M) = 2/3

Since the buffer capacity is less than 1, we can add a small amount of NaOH to raise the pH to 7.20 without a significant change in pH. We can calculate the volume of 0.300 M NaOH solution needed to raise the pH by 0.20 units:

Volume of NaOH = (Buffer capacity) * (Change in pH) * (Volume of solution)

= (2/3) * (0.20) * (1 L) = 0.133 L

So, we need to add 0.133 L of 0.300 M HCl to 1 L of 0.200 M anserine solution to reach a pH of 7.20.

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Answer:

a soft, spongy material that may be changed into coal

Explanation:

Answer:

0.086

Explanation:

got it on acellus

The mass of the dry solute recovered from the given data is 0.086 g.  Option C

To determine the mass of the dry solute recovered, we need to subtract the mass of the boat from the mass of the boat with the dry solute.

Given the data provided:

Boat Mass: 0.730 g

Boat + Solution: 0.929 g

Boat + Dry: 0.816 g

To find the mass of the dry solute, we subtract the boat mass from the boat + dry mass:

Mass of Dry Solute = (Boat + Dry) - (Boat Mass)

Mass of Dry Solute = 0.816 g - 0.730 g

Mass of Dry Solute = 0.086 g

Therefore, the correct answer is c) 0.086 g.

The mass of the dry solute recovered from the given data is 0.086 g. It is important to note that the mass of the dry solute is obtained by subtracting the mass of the boat from the mass of the boat with the dry solute, as the boat mass represents the weight of the empty boat or container used in the experiment.

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The chemical formula for the cation present in the aqueous solution of Zn(C₂H₃O₂)₂ is Zn²⁺.

In this compound, Zn represents the symbol for zinc, and the subscript 2 indicates that there are two zinc ions present. The acetate ion, acts as the anion in the compound and balances the charge of the cation.

When dissolved in water, Zn(C₂H₃O₂)₂ dissociates into Zn²⁺ cations and C₂H₃O₂⁻ anions. Zinc cations are positively charged due to the loss of two electrons, resulting in a 2+ charge.

These cations are attracted to the negatively charged oxygen atoms in the acetate ions, forming the aqueous solution of Zn(C₂H₃O₂)₂+.

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Answer:

At -20°C the mercury state will be liquid

Explanation:

The melting point of a substance is the temperature at which it changes from solid state to a liquid state, and the boiling point is the temperature at which it changes from liquid state to a gaseous state.

If mercury melts at -39°C and boils at 356.9°C, it means that if the temperature is lower than -39°C, mercury will remain al solid state. Between -39°C and 356.9°C, the state of mercury will be liquid and, above 356.9°C mercury will remain at gaseous state.

So, at -20°C the mercury state will be liquid, because that temperature it is between -39°C and 356.9°C.

Number of feed = 555 pounds

Feed cost = $237.21

The main composition of algebraic expressions are:  

• 1. phrases/terms  

• 2. variable  

• 3. constants  

• 4. arithmetic operations  

• 5. coefficients  

• 6. exponent  

Initial weight = 82 pounds

Goal weight = 267 pounds

The difference in weight that must be achieved :

\(\tt 267-82=185~pounds\)

The pig will gain 1 pound for every 3 pounds of feed⇒ 1 pound weight=3 pounds of feed

The amount of feed must be given:

\(\tt 185~pounds~weight\times 3~pounds~feed=555~pounds~of~feed\)

Feed costs $21.37 per 50 pound bag, so for 555 pounds :

\(\tt (555~pounds\div 50)\times \$21.37=\$237.21\)

Answer:

V₂ = 29.88 L

Explanation:

Given data:

Initial volume = 20 L

Initial pressure = 14 KPa

Initial temperature = 205 K

Final temperature = 350 K

Final volume = ?

Final pressure = 16 KPa

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

V₂ = P₁V₁ T₂/ T₁ P₂  

V₂ = 14 KPa × 20 L × 350 K / 205 K × 16 KPa

V₂ = 98000 KPa .L. K /3280 K.KPa

V₂ = 29.88 L

Answer:

Will group 2 elements lose electrons to bond with nonmetals in group 17 in a

1:2 ratio?

Explanation:

Metals are electropositive in nature. This means that they loose electrons. Thus, metals form ionic bonds by loosing electrons to non metals.

Elements of group 2 have a valency of 2 while those of group 17 has a valency of 1 so the ratio in which group 2 elements bond with elements of group 17 is 1:2. Hence the answer.