Answer:
3g of NaI is needed to prepare 400.0 mL of 0.0500 M NaI solution.
Explanation:
A 0.0500M solution means that is 0.0500 moles of NaI per every 1000 mL of solution. Thus, to prepare 400mL:

Also, the molar mass of NaI is 127g/mol + 23g/mol = 150g/mol
Consequently, multiplying the molar mass of NaI by the moles the necessary mass is obtained:

Oxygen has 6 valence electrons, so B
Answer:
The sound waves travel from the outer ear and in through the auditory canal, causing the eardrum, or tympanic membrane, to vibrate. This, in turn, causes the three small bones, known as the ossicles, or the hammer, the anvil and the stirrup, in the middle ear to move.
Answer: 0.040 mol/l
Explanation: Molarity c = n/V (Concentration)
c = 0.060 mol / 1,5 l = 0,040 mol/l
Greenhouse effect is the natural phenomenon which makes the Earth's atmosphere favorable for any form of life. As the sun's rays radiates into the atmosphere, some are deflected while some are absorbed. The Earth reflects this back, causing the heat to be trapped. At night, this keeps the Earth warm enough. Without the greenhouse effect, nights would be too cold and days would be too hot that life cannot be sustained.