Molar mass Na = 23.0 g/mol
1 mol ---- 23.0 g
n mol ---- 69 g
n = 69 / 23.0
n = 3.0 moles
1 mole -------- 6.02x10²³ molecules
3.0 moles ---- ?
3.0 * 6.02x10²³ / 1
= 1.806x10²⁴ molecules
hope this helps!
Answer:
160m/s
Explanation:
To find V Use the following formula V= F*W
V= Velocity F= Frequency W= Wavelength
V=20*8
=160m/s
0.000001ppm
Explanation:
Mass of fluoride = 500g
Volume of water = 500000liters
Unknown:
Parts per million of fluoride = ?
Solution:
The parts per million is the amount of solute in milligram dissolved in a liter of water or milligram per kilogram of solvent
It is a unit used to express very small concentration.
we need to convert g - mg
500g = 500 x 10⁻³mg = 0.5mg
Concentration in parts per million = 
Concentration in parts per million = 
= 0.000001ppm
learn more:
Parts per million brainly.com/question/2854033
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Answer:
D, E and F
Explanation:
About tetrachloro cobalt complexes, the following facts have been observed
- Color of the tetrachloro cobalt complexes is blue.
- They do not decompose on heating that means synthesis of tetra chloro is endothermic.
About hexa aqua cobalt complexes, the following facts have been observed
- Color of the hexa aqua cobalt complexes is pink color.
- They decompose on heating and remain stable on cooling that means process of synthesis of hexa aqua cobalt complexes is exothermic.
Based on above, the correct statements are:
The correct is chloro cobalt complex is blue and aqua cobalt
complex is pink.
The chloro complex is favored by heating.
If the chloro complex is a product, then the reaction must be endothermic.
The correct options are D, E and F.
