help me please just w number 2&3

Answer:

Explanation:

1st convert given data into % per 100wt...

Total system mass = 63.0g + 5.90g = 68.9g

%Rb = 63.0g/68.9g x 100% = 91.4% per 100wt

%O  =  5.9g / 68.9g x 100% = 8.6%

Then follow the following sequence of calculations...

% => grams => moles => mole ratio => reduce to smallest whole no ratio => empirical ratio => empirical formula

%Rb = 91.4% => 91.4g/ 85.5g·mol⁻¹ =>1.069mole

%O  =   8.6% =>  8.6g/16g·mol⁻¹ => 0.5375mole

Rb:O => 1.069 : 0.5375

Reduce by dividing by the smaller mole value

1.069/0.5375 : 0.5375/0.5375 => 2 : 1 <=> empirical ratio

∴ Empirical Formula => Rb₂O

The molar mass of carbon (C) is 12.0107 u.

Answer:

Explanation:

The answer is 12.0107 u

Hope it helped you.

Plz mark me brainliest.

Answer:

C

Explanation:

The stem and leaves need sunlight to undergo photosynthesis, they will grow in such a way until they receive some sunlight.

One mole of zinc contains 6.02 × 10²³ Zn atoms or formula units. Hence,6.53 moles of Zn contains 3.9  × 10²⁴ Zn atoms.

One mole of a substance is its amount containing 6.02 × 10²³  atoms or molecules. This number is called Avogadro number. One mole of every elements contains Avogadro number of atoms.

Similarly one mole of every compound contains 6.02 × 10²³  molecules. The mass of one mole of compound is called its molar mass.

Zn is 30th element in periodic table. Zn is a transition metal.  One mole of Zn  contains 6.02 × 10²³ Zn atoms . Hence number of atoms of 6.53 moles is:

6.53  × 6.02 × 10²³  = 3.9 × 10²³ .

Hence, there will be 3.9 × 10²⁴  Zn atoms in 6.53  moles.

Find more on Avogadro number:

http://brainly.com/question/11907018

#SPJ5

Answer:

32.73%

Explanation:

To solve this problem, first find the molar mass of Al(OH)₃.2H₂O

 Atomic mass of Al  = 27g/mol

                            O = 16g/mol

                            H  = 1g/mol

Molar mass = 27 + 3(16 + 1) + 2(2(1) + 16)

                    = 27 + 51 + 36

                   = 114g/mol

Percentage composition  = [tex]\frac{36}{114}[/tex] x 100 = 32.73%

The molecular formula of a compound gives the actual number of atoms of various elements present in one molecule of the compound. The molecular mass is 92 g/mol. The correct option is C.

The empirical formula of a compound can be defined as the formula which gives the simplest whole number ratio of atoms of various elements present in one molecule of the compound.

The molecular formula of a compound is a whole number multiple of its empirical formula.

Molecular formula = n × Empirical formula

The value of 'n' can be obtained from the relation:

n = Molecular mass / Empirical formula mass

Here the value of n = 2. Then,

Molecular mass = n × Empirical formula mass

Empirical formula mass of NO₂ = 45.8 g

2 × 45.8 = 91.6 ≈ 92 g/mol

Thus the correct option is C.

To know more about empirical formula, visit;

https://brainly.com/question/14044066

#SPJ7

Answer:

The unit for mass is the kilogram (Kg).

Explanation:

Hope this helped!! <3 good luckk!!

Answer:

Friction of wind against the ocean surface

Answer:

0.1139952 is the answer

Explanation:

Answer: It means that the energy is being stored or preserved to be used at a later time.

Your question was a little vague, so if this isn't the answer you were looking for, just let me know and I'll fix it.

Hope this helps! Good luck! :D

Answer: Are there options? I think the answer is continents, but I don't really understand the question. Is continents an option?

Explanation:

Answer:

71%

Explanation:

Answer:

B D

Explanation:

hope this is right but not entirely sure

Answer:

b.) burning paper

Explanation:

Answer:

sodium chloride + silver nitrate = silver chloride

Explanation:

i believe this is correct, hope it helps :)

Answer:

470.4N

Explanation:

Given parameters:

Mass of Stephanie  = 48kg

Unknown:

Force she exerts while falling to the ground  = ?

Solution:

The force she exerts is her weight;

  Weight  = mass x acceleration due to gravity

  Now insert the parameters ands solve ;

  Weight  = 48 x 9.8 = 470.4N

Answer:

See explanation

Explanation:

You see, we must cast our minds back to Charles' law. Charles' law gives the relationship between the volume of a gas and temperature of the gas.

Now, Micheal left the balloon outside at a particular temperature and volume the previous night. Overnight, the temperature dropped significantly and so must the volume of the gas in the balloon!

Remember that Charles' law states that, the volume of a given mass of gas is directly proportional to its absolute temperature at constant pressure. Since the pressure was held constant, the drop in the volume of gas in the balloon can be accounted for by the drop in temperature overnight.

Answer:

2 Answers. This would be chemical energy that is converted to heat. The heat from the wick melts the wax which gets absorbed in the wick and then gets burnt (which is really oxidation) to produce heat energy as well as light energy.

Explanation:

A candle must undergo a chemical reaction in order to burn, producing heat and light. As a result, energy changes from chemical energy to heat and light energy. As a result, as a candle burns, chemical energy is transformed into heat and light energy.

Chemical energy is the energy that is released when chemical substances engage in a chemical reaction and change into other substances. Batteries, food, and gasoline energy are some instances of chemical energy storage media.

A type of potential energy associated with the structural organization of atoms or molecules is known as chemical potential energy. Chemical connections or interactions between molecules may have led to this configuration.

They are broken down into simpler molecules, such as glucose and amino acids, which are then either reassembled and stored in various forms, such as glycogen, or consumed as energy. Chemical energy in food is essential for giving our bodies the fuel they require to keep us alive and active.

Thus, energy changes from chemical energy to heat and light energy.

To learn more about chemical energy, follow the link;

https://brainly.com/question/7640132

#SPJ5

Answer:

2NaCl(l) => 2Na(s) + Cl₂(g)

Explanation:

Electrolysis of melt NaCl to form sodium (Na) metal and chlorine (Cl₂) gas.

This is a class of reaction called 'Decomposition Rxns'. For what it's worth, there are 6 distinct compound types that undergo breakdown by decomposition. The acronym C O A C H E can help remember them.

C - Carbonates => CaCO₃(s) => CaO + CO₂

O - Oxides of Metals => 2Fe₂O₃(s) => 4Fe°(s) + 3O₂(g)

A - Acids (Oxoacids) => H₂CO₃(aq) => CO₂(g) + H₂O(l)

C - Chlorates, Bromates & Iodates => 2KClO₃(s) => 2KCl(s) + 3O₂(g)

H - Hydroxides => Ca(OH)₂(s) => CaO(s) + H₂O(l)

E - Electrolysis => see above electrolysis of NaCl(l)

Answer:

2NaCl(l) => 2Na(s) + Cl₂(g)

Explanation:

The molecular mass of gas = 44 g/mol

Given

5.6 Liters of gas

11 gram of gas

Required

The molecular mass

Solution

STP = Standart Temperature and Pressure , 1 atm 273 K

At STP , 1 mol gas = 22.4 L

So mol of 5.6 Liters gas :

= 5.6 : 22.4

= 0.25 moles

The molecular mass of gas :

= mass : mol

= 11 g : 0.25 moles

= 44 g/mol

Answer:

SO4²

Explanation:

Formula and structure: The sulfate ion formula is SO42- and the molar mass is 96.06 g mol-1. This salt is formed by one sulfate center to which 4 atoms of oxygen are attached, 2 of these atoms are forming S=O.

Answer:

[tex]so _{4} ^{2 - } [/tex]

Explanation:

sulfate is consisting of sulfur element with 4 oxygen as the structure in the pic given and this group is 2- charged

Answer:

Its has a lower density. Think about it, a ship in the water is long because if it wasn't it would have a higher density and sink. The ship needs to diperse its weight across the water to make it less dense.

Explanation:

Your welcome! Have a great day!

Answer:

sodium carbonate

Explanation:

Sodium hydrogen carbonate (also known as sodium bicarbonate or bicarbonate of soda) has the chemical formula NaHCO3. When it is heated above about 80°C it begins to break down, forming sodium carbonate, water and carbon dioxide. This type of reaction is called a thermal decomposition.

hope it helps! please mark me brainliest

thank you! have a good day ahead

if u follow me, I will follow u back

Answer: The correct option is A ( Break the crackers into pieces.)

Explanation:

The rate of reaction between two substances can be affected by the following factors:

--> surface area of reacting substances

--> concentration

--> reaction mechanism

--> temperature

--> the presence of a catalyst and

--> pressure ( if gaseous)

Reagents in solution tend to react faster than reagents in solid form. This is because molecules are freer to move about and collide more effectively in solutions. For example, a lump of zinc will not react as fast as powdered zinc with dilute hydrochloric acid to produce hydrogen. This is the same with the reaction between the crackers and soup. To increase the reaction of the substances, the crackers needs to be broken into pieces(thus,increased surface area)

Answer:

399.88 [tex]\frac{4.05*10^{23} }{6.022*10^{23} }[/tex] =269

Explanation:

399.88 is the molar mass of iron(III) sulfate.

The mass of 4.05 × [tex]10^{23[/tex] formula units of Fe2(SO4)3 is approximately 6.48 × [tex]10^{25[/tex] grams.

To calculate the molar mass of Fe2(SO4)3, we need to determine the atomic masses of the individual elements involved and multiply them by their respective subscripts:

Fe2(SO4)3 consists of 2 iron atoms, 3 sulfur atoms, and 12 oxygen atoms:

Molar mass of Fe2(SO4)3 = (2 * 55.845) + (3 * 32.06) + (12 * 16.00) = 159.69 g/mol

To calculate the mass of 4.05 × 10^23 formula units of Fe2(SO4)3, we can use the molar mass:

Mass = (4.05 × 10^23) * (159.69 g/mol) = 6.48 × 10^25 g

Rounded to two decimal places, the mass of 4.05 × [tex]10^{23[/tex] formula units of Fe2(SO4)3 is approximately 6.48 × [tex]10^{25[/tex] grams.

More on formula units can be found here: https://brainly.com/question/33740227

#SPJ6

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.

Learn more about matter,here:

https://brainly.com/question/13556931

#SPJ2