Answer:
0.136g
Explanation:
A student dissolved 5.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution. He took 4.00 mL of the stock solution and then diluted it with water to give 275. mL of a final solution. How many grams of NO3- ion are there in the final solution?

Initial mole of Co(NO3)2 

Mole of Co(NO3)2 in final solution

Mole of NO3- in final solution = 2 x Mole of Co(NO3)2

Mass of NO3- in final solution is mole x Molar mass of NO3

Hey there !
The answer is C. build up of electrical charges by friction
Static electricity is a stationary electric charge, typically produced by friction, which causes sparks or crackling or the attraction of dust or hair.
Hope this helps !
The movement of the Earth's plates is called Plate Tectonics. Hope this helps! :D
Answer:
Should be number 4, quartz.
Explanation:
Quartz is rougher than calcite, therefore it's able to scratch it.
Increasing order of magnitude of lattice energy is rbi <K2s< Mgs < Ga2O3.
Lattice energy is the energy change upon the formation of one mole of a crystalline ionic compound from its constituent ions. It depends upon the charges of the ion and the distance between the center of the ion when they are packed in the form crystal. Basically lattice energy is determined by the charge of the atom and the atomic radii of the atoms.
In Ga2O3, Ga has 3+ and O has 2- ions .so it has the lattice energy of 6.this is calculated by multiplying q1 and q2 .this attracts strongly.
In rbI , R has +1 and i has -1.so it ha lattice energy of -1.ther is no strong attraction nor lattice energy.
In Mgs, Mg has +2 and s has -2 .this is not as strong as Ga2o3 but stronger than rbi.
In K2S, k has =1 and s has 2-.this is stronger than rbi.
To learn more about Lattice energy please visit :
brainly.com/question/13169815
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