Answer:
100ml of a stock 50% KNO3 solutions are needed to prepare 250ml of a 20% KNO3 solution.
Explanation:
In the given question it is mentioned that
S1=50%
V2=250ml
S2= 20%
We all know that
V1S1=V2S2
∴V1= V2×S2÷S1
∴V1= V2S2×1/S1
∴V1= 250×20÷50
∴V1= 100ml
The Answer is D: Reactor products charge huge batteries.
Mathematics (from Greek μάθημα máthēma, "knowledge, study, learning") includes the study of such topics as quantity,[1] structure,[2] space,[1] and change.[3][4][5]
Mathematicians seek and use patterns[6][7] to formulate new conjectures; they resolve the truth or falsity of conjectures by mathematical proof. When mathematical structures are good models of real phenomena, then mathematical reasoning can provide insight or predictions about nature. Through the use of abstraction and logic, mathematics developed from counting, calculation, measurement, and the systematic study of the shapes and motions of physical objects. Practical mathematics has been a human activity from as far back as written records exist. The research required to solve mathematical problems can take years or even centuries of sustained inquiry.
Rigorous arguments first appeared in Greek mathematics, most notably in Euclid's Elements. Since the pioneering work of Giuseppe Peano (1858–1932), David Hilbert (1862–1943), and others on axiomatic systems in the late 19th century, it has become customary to view mathematical research as establishing truth by rigorous deduction from appropriately chosen axioms and definitions. Mathematics developed at a relatively slow pace until the Renaissance, when mathematical innovations interacting with new scientific discoveries led to a rapid increase in the rate of mathematical discovery that has continued to the present day.[8]
Mathematics is essential in many fields, including natural science, engineering, medicine, finance, and the social sciences. Applied mathematics has led to entirely new mathematical disciplines, such as statistics and game theory. Mathematicians engage in pure mathematics (mathematics for its own sake) without having any application in mind, but practical applications for what began as pure mathematics are often discovered later.[9][10]
~Wikipedia
Valence is the same in every family... except for transition metals, it goes from 1-8
dk if that helped
To do this, what we need to do is find the mass of PbCl2 as a whole, and the masses of Pb and Cl2 on their own.
So, the mass can be found by locating the atomic mass on the periodic table! It is that easy :)
The mass of Pb is 207.2
The mass of Cl2 is 70.906, since the mass is 35.453 and we have two of them.
When we add it together, the total mass of PbCl2 is 278.106, all we need to do is add the two masses we calculated before, together!
The formula for percent composition is:
element mass
---------------------- x 100
compound mass
So, lets do the % composition of Pb first.
207.2
---------
278.106
When we divide the two and multiply that answer by 100, we get 74.5%. So, the percent composition of Lead is 74.5%.
Now, lets do the same for Cl!
70.906
------------ x 100
278.106
The answer we get for that is 25.5%. So, that is the percent composition of Cl in PbCl2.
Hope I could help! :)
