.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Complete and balance the neutralization reactions given below.
a) 2KOH + H2SO4 —>
b) NaOH + HBr —>
c) NaOH + CH2COOH —>
d) 3Mg(OH)2 + 2H3PO4 —>
e) Ca(OH)2 + H2SO4 —>
f) Ca(OH)2 + 2HCl —>
Solutions:
a) 2KOH + H2SO4 —> K2SO4 + 2H2O
b) NaOH + HBr —> NaBr + H2O
c) NaOH + CH2COOH —>CH2COONa + H2O
d) 3Mg(OH)2 + 2H3PO4 —>Mg3(PO4)2 + 6H2O
e) Ca(OH)2 + H2SO4 —> CaSO4 + 2H2O
f) Ca(OH)2 + 2HCl —> CaCl2 + 2H2O
When a 2-mole mixture of CH4 and C2H4 gases is completely burned, 110 g of CO2 gas is formed. What are the moles of gases in the mixture? (H:1, C:12, O:16)
Solution;
I will talk about a short solution to such questions. You don’t need to balance the long reaction. That is to say, there should be a C atom in a single product in entrants and products, which is exactly the situation we mentioned in our question. In other words, CO2 should be formed as much as the C contained in the compound in the entrants. We can write it as follows.
CH4 ——> CO2
C2H4 ——–>2CO2
If we say x to the mole of CH4, we get C2H4 = 2-x moles.
CH4 ——> CO2
xmol______xmol
C2H4 ——–>2CO2
2-xmol____2(2-x)mol
44x grams from CH4.
from C2H4
1molCO2 44 grams
2.(2-x) moles CO2 a grams
__________________________________
a=88.(2-x) grams
44x+176-88x = 110
44x= 66
x=3/2=1.5 moles
So CH4 1.5 moles
C2H4 =2-x mol = 2-1.5 = 0.5 mol.
300 grams of insoluble water vapor from a 25% NaOH solution by mass becomes 40% in solution.
How many grams is the first solution?
a) 850
B) 800
C) 750
D) 700
E) 650
Solved
m1.%1 =%son.mson
25.x = 40.(x-300)
5x=8x-2400
3x=2400
x=800
first solution mass= 800 grams
How many moles of atoms does 4 moles of NH3 gas contain?
solved
1 mole NH3 3 moles H atom contain
4 moles NH3 x moles H atom contain
——————————————————
X = 12 moles H atom contain
What is the mass number of an atom with 21 protons, and 23 neutrons? (Just add the numbers)
Solved
mass number = protons number + notrons number
mass number = 21 + 23 =44
An atom that contains 17 protons and 18 neutrons. What element is it? (Just look at the Periodic table)
solved
1s2 2s2 2p6 3s2 3p5
This element finds 3rd period in 7A group in the periodic table
This element name is Brom.
C2H6 + O2 ——-> CO2 + H2O
What is the coefficient of O2 when the above chemical equation is balanced with the smallest integers?
A) 3 B)4 C)7/2 D)7 E)9
Solution;
Chemical equations are balanced according to the principle of “Conservation of atomic number and type”.
In the equation, we take the floor number of the substance, which is crowded in terms of the number of atoms, as 1, and first we balance the atomic numbers in this substance. We usually look at the latest oxygen count.
The equation is balanced as
1C2H6 + 7/2 O2 ——-> 2 CO2 + 3 H2O.
However, the question asks what is the coefficient of O2 when it is balanced with the smallest integers. In other words, he wants all the coefficients in the reaction to be integers. (In other words, he does not want rational numbers in the coefficients.) Then we save the fraction by multiplying the denominator of the fractional number in the reaction with the coefficients of the whole equation.
We multiply the coefficients for this reaction by 2;
2C2H6 + 7 O2 ——-> 4 CO2 + 6 H2O
The answer is D.
If 20% by mass of X2Y6 is y, what is the atomic mass of element x? (Y:1)
Solved
When we compare the percentages by mass, we find the ratio between the masses of the elements that make up the compound.
In addition, the entire compound is 100%. If 20% is Y, 80% is X.
mX/mY = 80/20 =4/1
X2Y6
2.X/6.Y= 4/1
If we substitute the atomic mass of Y, we can find the atomic mass of X.
2X/6.1 = 4/1
x=12
In chemical equation balancing, “number and kind of atoms are conserved.” are taken into account.
| Mg + 1/2O2 → MgO |
| KCIO3 → KCI + 3/2O2 |
| 2NaCl + F2 → 2NaF + Cl2 |
| H2 + 1/2O2 → H2O |
| 2AgNO3 + MgCl2 → 2AgCl + Mg(NO3)2 |
| 2AlBr3 + 3K2SO4 → 6KBr + Al2(SO4)3 |
| CH4 + 2O2 → CO2 + 2H2O |
| C3H8 +5 O2 → 3CO2 + 4H2O |
| C8H18 + 25/2O2 → 8 CO2 + 9H2O |
| FeCl3 + 3NaOH → Fe(OH)3 + 3NaCl |
| 2P + 5/2O2 → P2O5 |
| Na + H2O → NaOH + 1/2H2 |
| Ag2O → 2Ag +1/2 O2 |
| S8 + 12O2 → 8SO3 |
| 6CO2 + 6H2O → C6H12O6 + 6O2 |
| 2K + MgBr2 → 2KBr + Mg |
| 2HCI + CaCO3 → CaCl2 + CO2 + H2O |
| 4Al + 3O2 –> 2Al2O3 |
| Na + 1/2O2 → Na2O |
| C2H4 + 3O2 → 2CO2 + 2H2O |
| 2NaOH + H2SO4 → Na2SO4 +2 H2O |
| Al + 3 HCl → AlCl3 + 3/2 H2 |
| H2 + F2 → 2HF |
| C2H5OH + 7/2O2 → 2CO2 + 3H2O |
| CaCO3 → CaO + CO2 |
| H2SO4 + Ca(OH)2 → CaSO4 + 2H2O |
| Mg + 2HBr → MgBr2 + H2 |
| HNO3 + KOH → KNO3 + H2O |
| C + 1/2O2 → CO |
| C + O2 → CO2 |
| N2 + 3H2 → 2 NH3 |
| 3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O |
| 2Al + 3 H2SO4 → Al2(SO4)3 + 3H2 |
| 2N2 + 5O2 –>2N2O5 |
How many grams are there in 5.00 moles of hydrogen dioxide?
Solved
In order to solve the question, it is necessary to be able to write the “hydrogen dioxide” formula.
The hydrogen dioxide formula is H2O.
Molecular mass of H2O = 2.H + O = 2.1+16=18 gr/mol
1 moles H2O 18 gr/mole
5 moles H2O x
_________________________
x=90 grams H2O
Kimya Soruları 