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gogolik [260]
3 years ago
5

Fill In The Blanks:

Chemistry
1 answer:
yawa3891 [41]3 years ago
5 0

Answers : Fill in the blanks.


Answer 1) During a chemical reaction, the sum of the masses of the reactants and products remain unchanged.


In a reaction masses of the reactants and products always remains the same.


Answer 2) In a pure chemical compound, elements are always present in a definite proportion by mass.


It is observed that in a chemical reaction the elements are found in definite proportion by mass.


Answer 3) Clusters of atoms that act as an ion are called polyatomic ions.


Polyatomic ions are those ions which consits of atoms more than two in their molecule.


Answer 4) In ionic compounds, the charge on each ion is used to determine the chemical formula of the compound.


The charges on the molecule helps to determine the chemical formula of any compound.


Answer 5) The Avogadro constant 6.022 X 10^{23} is defined as the number of atoms in exactly 12 g of carbon-12


Avogadro used carbon-12 as the standard reference element fpr determining its molecules.


Answer 6) Mass of 1 mole of a substance is called its molar mass or molecular weight.


A molecular weight of an atom to define its number of moles.


Answer 7) The abbreviation used for length names of elements are termed as their Symbols.


The abbreviation used for the length of names of elements are called as symbols.


Answer 8) A chemical formula is also known as a true formula or molecular formula.


The term chemical formula determines the number of chemical components present in it.

Answer 9) Those ions which are formed from single atoms are called monoatomic ions.


The ions made up from single atoms are called as monoatomic ions.


Answer 10) Ionic compounds are formed by the combination between metal and nonmetal.


The ionic compounds are usually bonded by the ionic bonds in a compound.


Answer 11) The valency of an ion is equal to the charge on the ion.


Valency of any ion is always equal to the charge on that ion.


Answer 12) Mole is a link between the mass of a substance and number of formula units.


Usually the mole forms a link to define the mass of the substance and its formula.


Answer 13) The SI unit of amount of a substance is mole.


Mole is considered to be the SI unit for aount of substance of any chemical compound.

Answer : true or false.


Answer 1) Formula mass of Na_{2}O is 62 amu True


As we know there are 2 moles of Na and one mole of O so it will be (2 X 23) + 16 = 62 amu.


Answer 2) Those particles which have more or less electrons than the normal atoms are called ions True


We call ions to those atoms which hav more or less electrons in their normal atoms


Answer 3) Formula for sulphur dioxide is SO_{3}. False



The formula for sulphur dioxide  is SO_{2} as the name di suggests two molecules.


Answer 4) Molar mass of ethyne (C2H2) is 26 g/mol True.


As the ethyene molecule consists of 2 C atoms and 2 H atoms it will be (12 X 2) + (2 X 1) = 26


Answer 5) 22 gm of CO2 consists of 1 mole. False

 


The 1 mole of CO_{2} contains 1 C atom and 2  O atoms (12) + (16 X 2) = 44


Answer 6) Number of molecules in 32 gram of oxygen is 6.02 x 10^{23}. False


Only 1 moles of any substance will consist of 6.02 x 10^{23} molecules.


Answer 7) Water is an atom False.


Water is a molecule of 2 atoms namely hydrogen and oxygen.


Answer 8) Formula for sulphur dioxide is SO_{2} true.


As the name suggest sulphur along with two oxygen in it.


Answer 9) Clusters of atoms that act as an ion is called polyatomic ion. True


The clusters of ions from different atoms of the elements can be called as polyatomic ions.


Answer 10) Mass of 1 mole of a substance is called its formula mass. False.


As in formula mass we take the sum of the atomic weights of atoms in a molecule. And for 1 mole of a substance it is called as molar mass.


Answer 11) In a pure chemical compound, elements are always present in a definite proportion by mass. True


In any chemical reaction, the pure chemical compound is always found to have elements with definite proportion to their masses.


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Ratling [72]

Answer:

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6 0
3 years ago
John dalton postulated several statements about the atom. which statement did he NOT state?
algol [13]

Answer:

The atom is divisible particle and can be subdivided into smaller particles proton, neutron and electrons was not stated by John dalton.

Explanation:

The postulate of Dalton's atomic theory  that atom is indivisible particle and can not be subdivided into smaller particles was later changed because atom can be divided into neutrons, protons and electrons.

Electron:

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

Symbol= e⁻

Mass= 9.10938356×10⁻³¹ Kg

It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

Proton and neutron:

While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.

Symbol of proton= P⁺

Symbol of neutron= n⁰  

Mass of proton=1.672623×10⁻²⁷ Kg

Mass of neutron=1.674929×10⁻²⁷ Kg

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron.

7 0
3 years ago
Methanol, CH3OH, is the simplest of the alcohols. It is synthesized by the reaction of hydrogen and carbon monoxide. Write chemi
Serhud [2]

Answer:

The limiting reactant is H₂

Explanation:

The reaction of hydrogen (H₂) and carbon monoxide (CO) to produce methanol (CH₃OH) is the following:

2H₂(g) + CO(g) → CH₃OH(g)

From the balanced chemical equation, we can see that 1 mol of CO reacts wIth 2 moles of H₂. So, the stoichiometric ratio is:

2 mol H₂/1 mol CO = 2.0

We have 500 mol of CO and 750 mol of H₂, so we calculate the ratio to establish a comparison:

750 mol H₂/500 mol CO = 1.5

Since 2.0 > 1.5, we have fewer moles of H₂ than are needed to completely react with 500 moles of CO. In fact, we need 1000 moles of H₂ and we have 750 moles. So, the limiting reactant is H₂.

8 0
3 years ago
What mass of CaSO3 must have been present initially to produce 14.5 L of SO2 gas at a temperature of 12.5°C and a pressure of 1.
german
When the reaction equation is:

CaSO3(s) → CaO(s) + SO2(g)

we can see that the molar ratio between CaSO3 & SO2 is 1:1 so, we need to find first the moles SO2.

to get the moles of SO2 we are going to use the ideal gas equation:

PV = nRT

when P is the pressure =  1.1 atm

and V is the volume = 14.5 L 

n is the moles' number (which we need to calculate)

R ideal gas constant = 0.0821

and T is the temperature in Kelvin = 12.5 + 273 = 285.5 K

so, by substitution:

1.1 * 14.5 L = n * 0.0821 * 285.5

∴ n = 1.1 * 14.5 / (0.0821*285.5)

       = 0.68 moles SO2

∴ moles CaSO3 = 0.68 moles

so we can easily get the mass of CaSO3:

when mass = moles * molar mass

and we know that the molar mass of CaSO3= 40 + 32 + 16 * 3 = 120 g/mol


∴ mass = 0.68 moles* 120 g/mol = 81.6 g
7 0
3 years ago
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Mrac [35]
I believe it’s because they are trying to find other things that won’t pollute the environment as much, and they are also doing this because we are trying to reduce green house gas. Sorry if i’m wrong :(
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