How to calculate the number of molecules in 18g of H2O

Answer:

19.5g

Explanation:

Given parameters:

Volume of propane gas = 9.95L

Unknown:

Mass of propane gas =  ?

Solution:

To solve this problem, find the number of moles first.

    At STP;

        22.4L of gas makes up 1 mole

         9.95L of gas will have a [tex]\frac{9.95}{22.4}[/tex]    = 0.44mole

So;

   Mass of propane gas  = number of moles x molar mass

Molar mass of propane  = 3(12) + 8(1)  = 44g/mol

    Mass  = 0.44 x 44  = 19.5g

We use roman numerals to indicate the oxidation state of metal atoms when naming compounds especially in the case of coordination compounds. It is a standard system of nomenclature.

Oxidation state of a species is the number electrons gained or lost. Oxidation state increases if electrons are lost from the atom and it will be decreased if electrons are gained.

For example, copper is in + 2 oxidation state in CuSO₄, thus it can be indicated as Cu(II). Copper can exists is +3 oxidation too. Thus the representation will be Cu (III).

All the transition metals like copper exhibit various oxidation state. So it is important to indicate in which oxidation state they are in a particular compound. In the compound Fe₂O₃, iron is in + oxidation state whereas in FeSO₄, it can be +2 . Thus it is important to note whether it is Fe (II) or Fe (III).

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Answer: Mutations can cause instant adaptations, while natural selection is the process by which adaptations occurs over a series of generations. Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment. A mutation is an alteration of the DNA sequence.

Answer:

Pseudoscience

Explanation:

Predicting the future based solely on the position of the planets is an example of pseudoscience.

Pseudoscience is a body of knowledge that is not based on the scientific method but on some unverifiable/unprovable claims.

Predictions about the future can only be valid if it is based on the scientific method, not just about the position of the planet. The scientific method involves observation, hypothesis formulation, testing of the hypothesis through repeatable experiments, and arriving at conclusion.

Any other statement or belief that is not based on these procedures is said to be pseudoscientific.

Answer:

The answer to your question is pseudoscience.

Explanation:

I took the module 1 exam and got it right, yesterday.

Answer:

Explanation:

Solution required is .15 M 500 mL sodium fluoride .

molecular weight of sodium fluoride = 42

one mole of sodium fluoride = 42 grams

No of moles contained in the solution of .15M , 500 mL solution

= .15 x 0.5 moles = .075 moles

1 mole = 42 g

.075 moles = .075 x 42 = 3.15 grams .

So mass of sodium fluoride required = 3.15 g .

The mass of an object is the product of its volume and density. The mass of a the object with a volume of 825 cm³ and a density of 13.6 g/cm³ is 11220 g.

Density of substance is the measure of its mass per unit volume. It describes how closely its particles are packed. Density depends on the bond type, temperature and pressure.

Volume of the object is the space occupied by its particles. Volume can be expressed in L, ml, cm³, dm³ etc. Only solids and liquids has a definite volume and the volume of gases is that of the container.

Give that, volume of the object = 825  cm³

density =  13.6 g/cm³

Mass = volume × density

m = 825  cm³ ×  13.6 g/cm³ = 11220 g

Therefore, the mass of the object is 11220 g.

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Answer:

D Nimbostratus

Explanation:

Answer: B

Explanation: A fluorine atom has nine protons and nine electrons, so it is electrically neutral. (neutral =0)

The nucleus of a fluorine atom has a charge of zero as the atom has equal number of positive and negative charges.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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Answer:

Grass

Explanation:

On a hot summers day, while barefoot Concrete normaly has heat absorbed into it. (Or on top) So when you go to Walk on it, It normally burns the heel.

Hope I helped and Have a great day!

brainliest?

Answer:

grass

Explanation:

the concrete has a higher specific heat capacity and is basically hotter than the grass which has a lower one

Answer: Reactant

Explanation:

In simple wording, Water act as a reactant and it broke or we can say split the larger molecule in the smaller ones, The H and OH bonds are attached to the two products that are formed after the reaction. Another process in which water is used as an important reactant is photosynthesis.

Answer:

Explanation:

The trick here is to realize that if you know the volume of a gas at STP, you can use the fact that

1

mole of any ideal gas occupies

22.7 L

under STP conditions to calculate how many moles of gas you have in your sample.

Under STP conditions:

1 mole of an ideal gas = 22.7 L

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

In your case, you know that your sample of gas occupies

2.28 L

under STP conditions, which are currently defined as a pressure of

100 kPa

and a temperature of

0

∘

C

.

This means that your sample will contain

2.28

L

⋅

molar volume of a gas at STP



1 mole gas

22.7

L

=

0.10044 moles gas

Now, the molar mass of the gas is the mass of exactly

1

mole of the gas. In your case, you know that you get

3.78 g

for every

0.10044

moles, which means that you have

1

mole

⋅

3.78 g

0.10044

moles

=

37.6 g

Since this is the mass of

1

mole of gas, you can say that the molar mass of the gas is

molar mass = 37.6 g mol

−

1

−−−−−−−−−−−−−−−−−−−−−−−

Answer:

12 grams

Explanation:

Electrons do not contribute to mass. The proper unit to use is G

Answer: here is your answer

Explanation:

The oxygen family consists of the elements that make up group 16 on the periodic table: oxygen, sulfur, selenium, tellurium, and polonium. These elements all have six electrons in their outermost energy level, accounting for some common chemical properties among them.

Answer:

they all have 6 valence electrons

Explanation:

all elements in group 16 have 6 valence electrons

Answer:

European stability mechanism

Answer:

They will have the same ear shape since their proteins connect in the same ways to determine ear shape.

Explanation:

I majored in Chemistry

Answer:

They will have the same ear shape since their proteins connect in the same ways to determine ear shape.

Explanation:

Answer:

here you go

Explanation:

5 elements and properties:

Boron- The chemical properties of boron are more similar to carbon and silicon than elements of its own group, although boron is more electron deficient. Boron has a high affinity for oxygen-forming borates, and reacts with water at temperatures above 100 °C to form boric acid and other boron compounds.

Carbon- As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. The most common isotope of carbon has 6 protons and 6 neutrons, and has an atomic mass of 12.0107 amu. Its ground state electron configuration is 1s22s22p2.

Nitrogen-  Nitrogen gas (chemical symbol N) is generally inert, nonmetallic, colorless, odorless and tasteless. Its atomic number is 7, and it has an atomic weight of 14.0067. Nitrogen has a density of 1.251 grams/liter at 0 C and a specific gravity of 0.96737, making it slightly lighter than air.

Oxygen- is the air you breath

Nickel- Nickel is a hard silver white metal, which forms cubic crystals. It is malleable, ductile, and has superior strength and corrosion resistance. The metal is a fair conductor of heat and electricity and exhibits magnetic properties below 345°C

5 compounds and properties:

Water - Formula: H2O = Hydrogen2 + Oxygen. ...

Hydrogen Peroxide - Formula: H2O2 = Hydrogen2 + Oxygen2 ...

Salt - Formula: NaCl = Sodium + Chlorine. ...

Baking Soda - Formula: NaHCO3 = Sodium + Hydrogen + Carbon + Oxygen3

Octane - Formula: C8H18 = Carbon8 + Hydrogen18

hope this helps

Answer:

it's easier to look it up

Explanation:

Answer:

A. avoid talking to Anna altogether and stay out of her way

B. ask her manager for advice

C. check with Gary to see if there is any gossip about what's going on with Anna

D. take a curt approach of her own to show Anna how it feels

Explanation:

ANSWER: B.

The mole fraction of sulfuric acid : 0.073

Given

3.75 M sulfuric acid solution that has density of 1.230 g/mL

Required

The mole fraction

Solution

3.75 M = 3.75 mol/L

For 1 L solution :

mass of solution = 1230 g

mass Sulfuric acid : 3.75 mol x 98 g/mol=367.5 g

mass water = 1230-367.5 = 862.5 g

mol water = 862.5 : 18 g/mol= 47.92

mol total = 3.75 + 47.92 = 51.67

mole fraction of sulfuric acid :

= 3.75 : 51.67

= 0.073

Answer: The state of maater for HgBr is solid.

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.  

A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.  

The balanced chemical equation is:

[tex]HgNO_3(aq)+KBr(aq)\rightarrow HgBr(s)+KNO_3(aq)[/tex]

Answer:

See explanation

Explanation:

We know that surface area is an important determinant factor in the study of reaction rate. This is the reason why finely divided marble chips react faster than lumps of marble in the reaction between marble chips and dilute HCl.

Now imagine that i have a lump of marble and i have finely divided marble. Then i also have a solution of 0.5 M dilute HCl. If i introduce 1g of the lump  of marble into 250 ml solution of the 0.5 M HCl in one beaker and introduce 1g of finely divided marble into another 250 ml solution of 0.5 M HCl in a separate beaker, we will notice that the finely divided marble chips reacts faster as evidenced by the quicker effervescence of CO2 gas from the later compared to the former.

Hence, smaller marble chips reacts faster with dilute HCl than a lump of marble.

Answer:

yes the above given answer is absolutely correct I agree with u man on the above.

Answer:

4

Explanation:

The following equation, which depicts the combustion of propane, is given in this question as follows:

C3H8 + 02 → CO2 + H2O

However, this equation is not yet BALANCED because the number of atoms of each element is not the same on the reactant and product side. To balance the equation, we make use of COEFFICIENT to ensure that the number of atoms of each element on both side correlates.

The balanced equation is as follows:

C3H8 + 502 → 3CO2 + 4H2O

Therefore, the coefficient for water (H2O) after balancing the equation is 4.

The study of chemicals is called chemistry.

The correct answer is D.

The equation is not yet BALANCED because the number of atoms of each element is not the same on the reactant and product sides.

To balance the equation, we make use of COEFFICIENT to ensure that the number of atoms of each element on both sides correlates.

After balancing the equation is as follows:

[tex]C_3H_8 + 50_2 → 3CO_2 + 4H_2O[/tex]

Hence, the correct answer is 4 which shows the balanced water.

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Answer:

Three main parts are Protons (pos charge) Neutrons (no charge) Electrons (negative charge) and the electron is found on the outside of the nucleus

Explanation:

Answer:

True

Explanation:

Sometimes you will need to convert from grams to moles, or moles to grams

Answer:

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

Explanation:

Multiply 2.8 by 10

Answer:

Explanation:

4

Answer:

It’s false

Explanation:

it could be true if the question mentioned alkaline solution

Answer:

True

Explanation:

Phenolphthalein is colorless in the presence of an acid and turns pink in the presence of a base.