Answer:
protons = atomic numbermass number = protons + neutronsatomic number = mass number - neutrons = 78-38 = 40
Explanation:
The law of definite proportions agrees with Dalton atomic theory.
What is Dalton atomic theory?
It state that all matters is made of very tiny particles called atom. atoms are individual particles which can not be created or be destroyed in a chemical reactions. Atoms of given elements are identical in mass and chemical properties. Atoms of
different elements have different masses and chemical properties.
The law of definite proportions also known as proust's law ,state that a chemical compound contain the same proportion of elements by mass.this law is one of the stoichiometry .
Thus ,
This is the reason why it is agrees with dalton atomic theory.
To know more about Dalton atomic theory click-
brainly.com/question/13157325
#SPJ1
Answer: 0.9375 g
Explanation:
To calculate the number of moles for given molarity, we use the equation:
.....(1)
Molarity of
solution = 0.75 M
Volume of
solution = 25.0 mL = 0.025 L
Putting values in equation 1, we get:
According to stoichiometry :
2 moles of
require = 1 mole of
Thus 0.01875 moles of
will require=
of
Mass of
Thus 0.9375 g of
is required to react with 25.0 ml of 0.75 M HCl
I really hope this helps I’ve been there too and I’m just doing this so I get the 20 words and I have the picture
Answer:
B and C
Explanation:
When we have to do a buffer solution we always have to choose the reaction that has the <u>pKa closer to the desired pH value</u>. When we find the pKa values we will obtain:
![pKa_1=-Log[6.9x10^-^3]=2.16](https://tex.z-dn.net/?f=pKa_1%3D-Log%5B6.9x10%5E-%5E3%5D%3D2.16)
![pKa_2=-Log[6.2x10^-^8]=7.20](https://tex.z-dn.net/?f=pKa_2%3D-Log%5B6.2x10%5E-%5E8%5D%3D7.20)
![pKa_3=-Log[4.8x10^-^13]=12.31](https://tex.z-dn.net/?f=pKa_3%3D-Log%5B4.8x10%5E-%5E13%5D%3D12.31)
The closer value is pKa2 with a value of 7.2. Therefore we have to use the second reaction. In which
is the <u>acid</u> and
is the <u>base</u>. Therefore the answer for the first question is B and the answer for the second question is C.