Answer:
pH = 3.65
Explanation:
given data
pKa of HNO2 = 3.40
nitrous acid (HNO2) = 0.110 M
NaNO2 = 0.200 M
to find out
What is the pH
solution
we get here ph for acidic buffer that is express as
pH = pKa + log(salt÷acid) ........................1
put here value and we get
pH = 3.40 + log(0.200÷0.110)
pH = 3.65
<u>Answer:</u>
<em>20, 44, 62 </em>
<em></em>
<u>Explanation:</u>
To find the number of atoms of each element, we multiply coefficient and subscript
For example 
contains
5 × 1 = 5 ,Ca atoms and
5 × 2 = 10, Cl atoms
If there is a bracket in the chemical formula
For example 
we multiply coefficient × subscript × number outside the bracket to find the number of atoms
(Please note: 3 is the coefficient, and if there is no number given then 1 will be the coefficient )
So
3 × 3 = 9 , Ca atoms
3 × 1 × 2 = 6, P atoms
3 × 4 × 2 = 24, O atoms are present.
So let us find the number of atoms of each element on the left side of the equation
Number of C atoms = 2 × 10 = 20
Number of H atoms = 2 × 22 = 44
Number of O atoms = 31 × 2 = 62
20, 44, 62 are the Answers.
Answer : The correct option is, Mass
Explanation :
As we know that there are 3 states of matter :
Solid state : It is a state in which the particles are closely packed and does not have any space between them. This state have a definite shape and volume.
Liquid state : It is a state in which the particles are present in random and irregular pattern. The particles are closely arranged but they can move from one place to another. This state have a definite volume but does not have a fixed shape.
Gaseous state : It is a state in which the particles are loosely arranged and have a lot of space between them. This state have indefinite volume as well as shape.
If we are taking 100 grams of ice then after melting its mass remains same but its shape, volume and temperature will be changed and after evaporation its mass remains same but its shape, volume and temperature will be changed.
Hence, the mass will stay constant, no matter if the substance is in the solid, liquid, or gas state.
Answer:
The answer is option 3, C5H12 + 8O2 → 5CO2 + 6H2O.
Explanation:
In an exothermic reaction, the energy change(ΔH) will always be a negative value.
For endothermic reaction, the energy change's value is positive.
In the options above, option 1 and 2 are endothermic reaction.
