Cs -137 has a half life of about 30 years. If 60 years pass, there is two half lives passed so 1/2 * 1/2= 1/4. Take 1/4 and multiply it with the mass given:
(1/4)*20mg=5mg left
D = 0.2 g / ml = 0.2 g / cm³
For example, density of steel is 7.85 g / cm³.
Density of pure water is 1.0 g/cm³. An object which has a density < 1.0 g/cm³ will float in water.
Answer: Material that has a density of 0.2 g/ml ( 0.2 g/cm³ ) is good for making couch cushions.
The temperature of water is cooler in deep oceans. The temperature there goes to 0°C to -3°C below which the water freezes. The water on the surface of the oceans and deep inside it varies because of the difference in energy of the two layers. One of the widest use of cold water is air conditioning. Cold water has a higher density than warm water. Water gets colder with profundity since chilly, salty sea water sinks to the base of the sea beds underneath the less dense hotter water close to the surface.
Answer:
Mg
Explanation:
Mg forms 2+ ions and mgcl2 has a melting point over 700°C I believe.