Please help me on this.

Explanation:

b. What useful functions do oxidation numbers  serve?

It is used to show oxidation and reduction (loss and gain of electrons)

b. How many molecules are in 1 mole of  molecules?

1 mole = 6.022 * 10^23 molecules

c. What is the name given to the number of  molecules in 1 mole?

Avogadro's Number of molecules

21. a. What is the molar mass of an element?

This is the mass of an element divided by the number of moles.

Molar mass = Mass / Number of moles

b. Write the molar mass rounded to two  decimal places of carbon, neon, iron and  uranium.

amu = Atomic Mass Unit

Carbon = 12.01 amu

Neon = 20.18 amu

Iron = 55.85 amu

Uranium = 238.03 amu

Answer:Calcium carbonate (CaCO3), essentially, is an ionic compound having the bivalent calcium and carbonate ions. But the carbonate anion is a polyatomic species. The carbon atom is bonded to all the three oxygen atoms by covalent bonds - two carbon-oxygen single bonds and one carbon-oxygen double bond.

Explanation:So it's ionic hope this helps u. Btw may i have brainlist plz.

Answer:

Na2SO4 means: two moles sodium (45.98 g), one mole sulfur (32.06 g), and four moles oxygen (64.00 g) combine to form one mole of sodium sulfate (142.04 g).

Explanation:

Answer:

As we can see in the formulae, Na₂SO₄

We can see that 4 is the subscript of O and that means There are 4 atoms of oxygen.

Answer: D. Synthesis

Explanation:

Sodium Oxide + Water = Sodium Hydroxide

The volume of carbon dioxide is formed is Option C i.e. 80 ml.

Given that,

Based on the above information, the calculation is as follows:

Here the volume should be 80ml

Therefore we can conclude that The volume of carbon dioxide is formed is Option C i.e. 80 ml.

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Answer:

[tex]\boxed {\boxed {\sf AlN}}[/tex]

Explanation:

The goal when forming compounds is to achieve a net charge of 0.

We are given aluminum with a charge of 3+  and nitrogen with a charge of 3-.

These charges are equal and opposite, so one of each will equal 0.

Therefore, we do not need any subscripts. List the metal's symbol (aluminum) then the nonmetal.

Th formula for the compound, which is aluminum nitride, is AlN.

Answer:

volume of brick= length × breadth × height

=0.000018 ×6.5×17.3

=

Answer:

temperature

Explanation:

Answer

The balanced reaction that describes the reaction between sulfur and oxygen to produce sulfur dioxide is expressed S(s) + O2 (g) = SO2 (g). In many manufacturing plants, sulfur dioxide is furhter reacted to oxygen to form sulfur trioxide then added with water to produce sulfuric acid.

Explanation: The balanced reaction that describes the reaction between sulfur and oxygen to produce sulfur dioxide is expressed S(s) + O2 (g) = SO2 (g).

Answer:

The balanced reaction that describes the reaction between sulfur and oxygen to produce sulfur dioxide is expressed S(s) + O2 (g) = SO2 (g). In many manufacturing plants, sulfur dioxide is further reacted to oxygen to form sulfur trioxide then added with water to produce sulfuric acid.

Answer: Earthquake location

Explanation:

Answer:

Volcano chains and arcs, and earthquake locations

hmm, i not sure i come back later with the answer.

Answer:

At each end of a magnet is a pole. These lines of flux (called a vector field) can not be seen by the naked eye, but they can be seen visually by using iron fillings sprinkled onto a sheet of paper or by using a small compass to trace them out.

hope it's help

Answer:

The liquid decreases in temperature and its particles lose kinetic energy.

Temperature is proportional to kinetic energy, so if temperature decreases, kinetic energy decreases. Energy has been removed from the liquid, because it is in the air

Answer:

The cholesterol in your blood comes from two sources: the foods you eat and your liver. Your liver makes all the cholesterol your body needs.

Emissions from motor vehicles increase smog in the air which can block radiation. Hence, option C is correct.

An urban area is a region surrounding a city. Most inhabitants of urban areas have nonagricultural jobs. Urban areas are very developed, meaning there is a density of human structures such as houses, commercial buildings, roads, bridges, and railways. "Urban area" can refer to towns, cities, and suburbs.

Emission from motor vehicles increases smog in the air that can block radiation, which makes sense because urbanization means more people in one area=lots of pollution.

Hence, option C is correct.

Learn more about urbanization here:

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Answer:

Describe how a sample of copper chloride crystals could be made from copper carbonate and dilute hydrochloric acid. Add excess copper carbonate to hydrochloric acid in a beaker, stirring until there is no further reaction. Filter the mixture to remove the remaining copper carbonate, then heat the remaining solution to the point of crystallisation.

Explanation: Hope this is right.

Answer:

The correct answer is 639 L H₂

Explanation:

We use the ideal gas equation:

We have the following data:

n = 28.3 mol

T= 297 K

P= 1.08 atm

R= 0.082 L.atm/K.mol (gas constant)

We introduce the data in the gas equation to calculate the volume (V):

PV=nRT

⇒V =nRT/P = (28.3 mol x 0.082 L.atm/K.mol x 297 K)/(1.08 atm) = 638.2 L ≅ 639 L

Therefore, the correct option is  639 L H₂

Answer:

639 L H2

Explanation:

took the quiz

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Answer:

homogeneous mixture

Answer:

19 m/s

Explanation:

57/3

Answer: It takes more energy to break the bonds of the reactants than is released when the  bonds in the products are formed

Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat. Thus it takes more energy to break the bonds of the reactants than is released when the  bonds in the products are formed

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat. Thus More energy is released when the bonds in the products are formed than is used to  break the bonds in the reactants

Answer:

Divide by the molar mass to get moles

Explanation:

Answer:

There are three ways to make solids dissolve faster: Break the solute into smaller pieces. Stir the mixture. * Heat the mixture.

Explanation:

Substances can dissolve in water three ways—by dissociation, dispersion, and ionization.

We can use the equation for dilutions that relates concentration and volume:

[tex]M_1V_1=M_2V_2[/tex]

where M is the molarity, V is the volume, and 1 and 2 refer to the initial and final states of the solution, respectively. Here, we are given the molarity of the initial solution and the volumes of the initial and final (diluted) solutions. To find the final concentration (i.e., the molarity of the diluted solution), we would be solving for M₂:

[tex]M_2=\frac{M_1V_1}{V_2} = \frac{(0.55 \text{ M})(145 \text{ mL})}{250 \text{ mL}} \\ M_2 = 0.319 \approx 0.32 \text{ M}.[/tex]

The molarity is given to two significant figures as both our M₁ and V₂ are given to two significant figures.

Note: Although our volumes are in mL instead of L, we do not need to convert them to L for the purposes of our calculation since we would be multiplying our V₁ and V₂ by a common factor that would cancel out in division. All that matters is the ratio between the two volumes, which is the same whether the volumes are in mL or in L.

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We follow the exact same procedure in the second question as we did in the first problem: solve for M₂ given M₁ = 9.02 M, V₁ = 35.0 mL, and V₂ = 45.0 mL:

[tex]M_2=\frac{M_1V_1}{V_2} = \frac{(9.02 \text{ M})(35.0 \text{ mL})}{45.0 \text{ mL}} \\ M_2 = 7.02 \text{ M}.[/tex]

Answer:

18 * 10^19 atoms

Explanation:

We must first convert 57.8 mg to grams.

If 1000 mg = 1g

  57.8 mg = 57.8/1000 = 57.8 * 10^-3 g

Now;

If 1 gold atom has a mass of 3.27X10^-22 grams

x gold atoms have a mass of 57.8 * 10^-3 g

x = 57.8 * 10^-3 g/3.27X10^-22 g

x = 18 * 10^19 atoms

Answer: The answer is 4320

Explanation:

I got the answer correct