Answer: A) Na+ and O2-
Explanation:
To know the electronic configuration, one has to determine the numbers of electrons present in each atom.
Na+ means a sodium atom that has lost one valence electron. A Sodium atom initially has 11 electrons, but having lost an electron making it 10 electrons remaining with electron configuration of 1s2 2s2 2p6.
O2- means oxygen atom that has gained two valence electrons. An oxygen atom initially has 8 electrons, having gained two electrons makes it 10 electrons with electron configuration of 1s2 2s2 2p6. same as Na+
The purpose of gaining or losing electrons is to attain a stable duplet or octet structure.
Natural selection requires variation between individuals. Mutations and reproduction increase genetic variation in a population. Natural selection occurs when environmental pressures favor certain traits that are passed on to offspring.
Answer:
Mass of Ca(OH)₂ required = 0.09 g
Explanation:
Given data:
Volume of HNO₃ = 25 mL (25/1000 = 0.025 L)
Molarity of HNO₃ = 0.100 M
Mass of Ca(OH)₂ required = ?
Solution:
Chemical equation;
Ca(OH)₂ + 2HNO₃ → Ca(NO)₃ + 2H₂O
Number of moles of HNO₃:
Molarity = number of moles / volume in L
0.100 M = number of moles / 0.025 L
Number of moles = 0.100 M ×0.025 L
Number of moles = 0.0025 mol
Now we will compare the moles of Ca(OH)₂ with HNO₃ from balance chemical equation.
HNO₃ : Ca(OH)₂
2 : 1
0.0025 : 1/2×0.0025 = 0.00125
Mass of Ca(OH)₂:
Mass = number of moles × molar mass
Mass = 0.00125 mol × 74.1 g/mol
Mass = 0.09 g
...... it's molecule.....
Matter can change to a solid depending on how hot or cold it is. I turns into a liquid if you melt it, and it turns into a gas when it evaporates.
