Emma is examining evidence from a robbery. She hypothesizes that the robber entered the home from the garage, but when she investigates this, she can't find any signs of forced entry or any physical evidence that supports this. What should her next step be?

A.
create another hypothesis

B.
conduct another experiment

C.
draw a conclusion

Answer:

Explanation:

100/56 = 1.79 moles MgS

56 came from the periodic table for Mg and S

Answer:

-lithium

-atomic number

-mass number

-protons

Explanation:

Answer: A

Explanation:

You thought i was feeling you that n was a munch

Explanation:

The chemical formula NH3 represents ammonia, a colorless gas that is widely used in various industrial and household applications. The formula indicates that one molecule of ammonia contains one nitrogen atom and three hydrogen atoms. Therefore, the ratio of nitrogen to hydrogen in ammonia is 1:3.

This means that for every one nitrogen atom in an ammonia molecule, there are three hydrogen atoms. Alternatively, we can say that the ratio of nitrogen atoms to hydrogen atoms in ammonia is 1:3.

The following sentences describe density: An object's density is constant. A derived unit of measurement called density An object's density determines whether it will float or sink.

Without affecting the thing's makeup, the mass of an object can be measured. The volume of an object is comparable in this regard. As a result, there is no requirement for a chemical reaction to determine an object's density, making density a physical feature.

Physical properties are characteristics of matter that are independent of changes in its chemical composition. Physical characteristics include things like density, colour, hardness, melting, and boiling points.

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Answer:

1.25 moles

Explanation:

The balanced chemical equation for the reaction between Ca and Cl to produce CaCl2 is:

Ca + Cl2 → CaCl2

The stoichiometry of the balanced equation tells us that one mole of Ca reacts with one mole of Cl2 to produce one mole of CaCl2. Therefore, to find out how many moles of Ca are required to react with 2.50 mol of Cl, we need to divide 2.50 mol of Cl by the coefficient of Cl2 in the balanced equation, which is 2:

2.50 mol Cl ÷ 2 = 1.25 mol Ca

Therefore, 1.25 moles of Ca are required to react with 2.50 mol of Cl to produce the compound CaCl2.

H+ (aq) + OH- (aq) → H2O (l)

Answer:

   A + B = AB is an example of a synthesis reaction

Explanation:

The value of the property at the end of the given time period is determined as $410,000.

The value of the property is the sum of the purchase price of the lot and the cost of building the home, which is:

$30,500 (purchase price of the lot) + $375,000 (cost of building the home) = $405,500

However, the bank has appraised the home at $410,000, which means that the value of the property has increased by $4,500.

Therefore, the value of the property is:

$405,500 (original value) + $4,500 (increase in value) = $410,000.

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The emission spectrum of copper can be seen from the spectrum C

An emission spectrum is the pattern of wavelengths of electromagnetic radiation emitted by a substance when it is excited by heat, electricity, or some other energy source. Each element, molecule, or compound has a unique emission spectrum, which can be used to identify it or to study its physical and chemical properties.

The emission spectrum is produced when electrons in the atoms or molecules are excited to higher energy levels, and then return to their ground state by releasing energy in the form of photons. The energy of each photon corresponds to a specific wavelength, and the collective emission of all the photons produces a characteristic pattern of bright lines or bands in the electromagnetic spectrum.

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If bond formation in the products releases more heat energy than bond breaking in the reactants does.

The reverse of exothermic processes is endothermic reactions. They take in thermal energy from the environment. This indicates that endothermic reactions cause their surroundings to get colder. This kind of response can be seen in the melting of ice.

An organism is said to be endothermic if it expends energy to control the internal temperature of its body. Ectothermic organisms, on the other hand, are those that control their body temperature through external environmental stimuli.

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We must first determine how much heat is produced by the combustion of aniline. According to the chemical equation, 4 moles of aniline react with 35 moles of oxygen to create 4 moles of nitrogen dioxide, 24 moles of carbon dioxide, and 14 moles of water. The mole ratio of aniline to heat emitted is as a result.

When one mole of water is created from hydrogen and oxygen in the opposite reaction (equation d), it exhales 285.8 kJ of energy.

How much heat energy is released when 1.8 g of glucose is burned?

C₆H₁₂O₆(s)+6O₂(g)→6CO₂(g)+6H₂O(l); ΔH = −2900kJ

One mole (about 180g) of glucose burned during combustion, releasing 2900kJ (29001801.8=29kJ) in heat.

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An example of solar energy being used in the U.S is in the heating of swimming pools, and powering of cabins in off grid regions.

14. Using hydrogen as a fuel source involves using it as a primary energy carrier to power vehicles or generate electricity. It can be combined with oxygen to create water, producing energy in the process. The process of using hydrogen as a fuel source is known as hydrogen fuel cell technology, which involves the conversion of chemical energy into electrical energy.

15. Hydrogen is the most abundant element in the universe but is rarely found in its pure form on Earth. It is usually found in combination with other elements such as oxygen in water, carbon in hydrocarbons, and nitrogen in ammonia. Hydrogen can be extracted from water, natural gas, coal, and biomass through various methods such as steam-methane reforming, electrolysis, and biomass gasification.

16. Advantages of using hydrogen as a fuel source include:

Disadvantages of using hydrogen as a fuel source include:

17. A fuel cell is an electrochemical device that converts chemical energy into electrical energy through a chemical reaction between hydrogen and oxygen. It consists of an anode, a cathode, and an electrolyte, with the hydrogen fuel entering the anode and the oxygen entering the cathode. The hydrogen molecules are split into protons and electrons, with the protons passing through the electrolyte and the electrons flowing through an external circuit, generating electricity. The oxygen combines with the protons and electrons at the cathode, producing water as the only byproduct.

18. Solar energy is a form of renewable energy that is derived from the sun's radiation. It is harnessed through various technologies such as photovoltaics, solar thermal systems, and concentrated solar power to generate electricity, heat water, and power homes and businesses.

19. A solar cell is a semiconductor device that converts sunlight directly into electricity through the photovoltaic effect. It is made of a thin layer of a semiconductor material such as silicon that is treated with impurities to create a p-n junction. When sunlight strikes the cell, it creates an electric field that separates the positively charged holes and negatively charged electrons, generating an electric current.

20. Advantages of using solar energy include:

Disadvantages of using solar energy include:

21. An example of solar energy being used in the U.S is in the heating of swimming pools, and powering of cabins in off grid regions.

To determine the number of HCl molecules in 4.91 L of HCl acid at 25°C, we can use the following steps:

[tex]\qquad\sf {Density = \dfrac{mass}{volume}}[/tex]

[tex]\qquad\sf{mass = density \times volume}[/tex]

[tex]\qquad\sf{mass = 1.096 \: g/mL \times 4.91\: L = 5.38\: kg}[/tex]

Convert the mass of HCl acid to the number of moles using its molar mass. The molar mass of HCl is 36.46 g/mol.

[tex]\sf{moles = \dfrac{mass}{ molar\: mass} = \dfrac{5.38\: kg}{36.46\: g/mol} = 147.6\: mol}[/tex]

Use Avogadro's number to convert the number of moles of HCl to the number of HCl molecules. Avogadro's number is [tex]6.02 \times 10^23[/tex] molecules/mol.

[tex]\sf number\: of\: HCl\: molecules = moles \times Avogadro's\: number[/tex]

[tex]\begin{aligned}\sf number\: of\: HCl\: molecules& =\sf 147.6 \: mol \times 6.02 \times 10^23\: molecules/mol \\& =\sf 8.88 \times 10^25\: molecules\end{aligned}[/tex]

Therefore, there are [tex]8.88 \times 10^25[/tex] HCl molecules in 4.91 L of HCl acid at 25°C, assuming the density of the acid is 1.096 g/mL.

[tex]\rule{200pt}{5pt}[/tex]

Answer: 1.0 X 10^-5 M

Explanation:

to change pOH to OH- it is judt 1 X 10-pOH

so it is 1 x 10^-5

Answer: D) 3.8 L

Explanation:

Boyles law

P1v1=p2v2

V2= p1v1/p2

v2= 1.0 x 5.0 /1.3 = 3.84 L

Answer:

To find the value of y, we need to use the concept of molar ratios and the mole concept.

First, we need to calculate the number of moles of aluminum and oxygen in the given sample of ore. We can do this by dividing the mass of each element by its respective atomic mass:

Number of moles of aluminum = 5.4 kg / 27 g/mol = 200 moles

Number of moles of oxygen = 4.8 kg / 16 g/mol = 300 moles

Next, we can determine the ratio of the number of moles of aluminum to oxygen in the sample. This ratio is:

Aluminum : Oxygen = 200 : 300

Simplifying this ratio by dividing both sides by 100, we get:

Aluminum : Oxygen = 2 : 3

According to the chemical formula of aluminum oxide (Al2O3), it contains 2 atoms of aluminum for every 3 atoms of oxygen. Therefore, the sample of ore must contain a whole number of units of this chemical formula. Let the number of units of Al2O3 be y.

Then, we can set up the following equation to solve for y:

2 moles of aluminum * y = 200 moles of aluminum

3 moles of oxygen * y = 300 moles of oxygen

Simplifying each equation, we get:

y = 100

y = 100

Since both equations give the same value for y, we can conclude that the sample of ore contains 100 units of Al2O3. Therefore, the value of y is 100.

Answer:

Explanation:

MTBE (C5H12O)

Esters, amines, and amides have many uses in medicine, and so do carboxylic acids, such as aspirin. Aspirin is the drug that will be investigated further. Its scientific name is acetylsalicylic acid.

Acetylsalicylic acid contains two functional groups: a carboxylic acid group (-COOH) and an ester group (-COO-CH₃). The carboxylic acid group is responsible for the acidic properties of aspirin and allows it to form salts with bases. The ester group is formed from the reaction between the carboxylic acid group of salicylic acid and acetic anhydride. This esterification reaction makes aspirin more soluble in organic solvents and less irritating to the stomach than salicylic acid.

Aspirin is a widely used medication that has anti-inflammatory, analgesic, and antipyretic properties. It works by inhibiting the production of prostaglandins, which are responsible for pain, inflammation, and fever. Aspirin is commonly used to treat headaches, fever, arthritis, and other inflammatory conditions. It is also used as a blood thinner to prevent heart attacks and strokes.

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In symbol form, ice is depicted as CO2, in particle form, as molecules of CO2 packed closely together, and in macroscopical form, as a white, crystalline substance that sublimates from a solid to a gas.

Because the gas when it solidifies resembles ice, ice ice is actually just carbon dioxide that has been solidified. Unlike regular ice, it instantly transforms into CO2 gas instead of melting into a liquid.

Solid carbon dioxide is sometimes referred to as "dry ice." That's because when something warms up and changes state, it doesn't just dissolve into a liquid. Instead, it skips the liquid step and transforms right into a gas.

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Problem 1:

we need 80 g of the 15% solution and 120 g of the 20% solution.

Let x be the mass of the 15% solution needed and y be the mass of the 20% solution needed.

x + y = 200 (total mass of the two solutions)

0.15x + 0.2y = 0.17(200) (total amount of solute in the two solutions)

Solving these equations,  x = 80 g and y = 120 g.

Therefore, we need 80 g of the 15% solution and 120 g of the 20% solution.

Problem 2:

we need 120 g of the 18% solution and 180 g of the 5% solution.

Let x be the mass of the 18% solution needed and y be the mass of the 5% solution needed.

x + y = 300

0.18x + 0.05y = 0.07(300)

Solving these equations, x = 120 g and y = 180 g.

Therefore, we need 120 g of the 18% solution and 180 g of the 5% solution.

Problem 3:

The mass percentage of the final solution is 135 g/550 g × 100% = 24.55%.

The total mass of the final solution is 200 g + 350 g = 550 g.

The total amount of solute in the final solution is:

0.15(200 g) + 0.20(350 g) = 65 g + 70 g = 135 g.

Therefore, the mass percentage of the final solution is 135 g/550 g × 100% = 24.55%.

Problem 4:

The mass percentage of the final solution is 110 g/335 g × 100% = 32.84%.

The total mass of the final solution is 300 g + 35 g = 335 g.

The total amount of solute in the final solution is:

0.15(300 g) + 35 g = 75 g + 35 g = 110 g.

Therefore, the mass percentage of the final solution is 110 g/335 g × 100% = 32.84%.

Problem 5:

The mass percentage of the final solution is 18.18%.

Calculate the final mass of the solution:

Final mass = 400 g + 150 g = 550 g

Calculate the mass of solute in the 25% solution:

Mass of solute = 0.25 x 400 g = 100 g

Calculate the mass percentage of the final solution:

Mass percentage = (mass of solute ÷ final mass) x 100%

Mass percentage = (100 g ÷ 550 g) x 100%

Mass percentage = 18.18%

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For each problem:

Problem 1:

Let x be the mass of the 15% solution needed and y be the mass of the 20% solution needed.

We have two equations:

x + y = 200 (total mass of the solution)

0.15x + 0.20y = 0.17(200) (total amount of solute in the solution)

Solving these equations:

x = 80 g (mass of 15% solution needed)

y = 120 g (mass of 20% solution needed)

Therefore, 80 g of 15% solution and 120 g of 20% solution need to be mixed to prepare 200 g of 17% solution.

Problem 2:

Let x be the mass of the 18% solution needed and y be the mass of the 5% solution needed.

We have two equations:

x + y = 300 (total mass of the solution)

0.18x + 0.05y = 0.07(300) (total amount of solute in the solution)

Solving these equations:

x = 120 g (mass of 18% solution needed)

y = 180 g (mass of 5% solution needed)

Therefore, 120 g of 18% solution and 180 g of 5% solution need to be mixed to prepare 300 g of 7% solution.

Problem 3:

Let x be the mass of the final solution.

The total amount of solute in the final solution is:

0.15(200 g) + 0.20(350 g) = 55 g + 70 g = 125 g

The total mass of the final solution is:

200 g + 350 g = 550 g

Therefore, the mass percentage of the final solution is:

(125 g / 550 g) x 100% = 22.7%

Problem 4:

Let x be the mass of the final solution.

The total amount of solute in the final solution is:

0.15(300 g) + 35 g = 80 g

The total mass of the final solution is:

300 g + 35 g = 335 g

Therefore, the mass percentage of the final solution is:

(80 g / 335 g) x 100% = 23.9%

Problem 5:

Let x be the mass of the final solution.

The total amount of solute in the final solution is:

0.25(400 g) = 100 g

The total mass of the final solution is:

400 g + 150 g = 550 g

Therefore, the mass percentage of the final solution is:

(100 g / 550 g) x 100% = 18.2%

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Global warming brought on by rising carbon dioxide concentrations in the atmosphere is changing weather patterns and ocean temperatures. Changes in precipitation patterns are being brought on by the warming of the atmosphere.

Because it is one of the gases in the atmosphere that causes the greenhouse effect, which causes the Earth to warm, carbon dioxide is known as a greenhouse gas. Long-wavelength infrared radiation (heat) from the Earth is absorbed by carbon dioxide molecules in the atmosphere, and some of it is then radiated back downward.

Similarly, as air temperatures rise in response to rising carbon dioxide concentrations, more water vapor escapes into  the atmosphere—which then amplifies greenhouse heating

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Answer:

Explanation:

convert to grams

0.133 mol C x 12 = 1.596

0.267 mol H x 1 = 0.267

Now subtract those numbers from the 4.00

4.00-1.596 -0.267 = 2.137 g O

Now convert grams O to moles

2.137 x (1mole O/16 g O) =0.1335625 moles O

3 sig figs = 0.134 moles O

Coarse and excellent adjustment The coarse adjustment knob  solely be used with the lowest electricity objective lens. Once it is in focus, you will only need to use the best focus. Using the coarse center of attention with greater lenses may result in crashing the lens into the slide.

You must have the object situated before you exchange objectives to increase the magnification, because the subject of view turns into smaller; if the object is off to the side, it might also disappear when you go to higher magnification.

The optics of a microscope's lenses alternate the orientation of the photo that the consumer sees. A specimen that is right-side up and going through proper on the microscope slide will appear upside-down and going through left when considered through a microscope, and vice versa.

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