Answer:
Density = 3
Explanation:
Density = Mass/volume
D = 45/15
D = 3
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Answer:
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Explanation:
it is too brief to type
Answer:
Considering the half-life of 10,000 years, after 20,000 years we will have a fourth of the remaining amount.
Explanation:
The half-time is the time a radioisotope takes to decay and lose half of its mass. Therefore, we can make the following scheme to know the amount remaining after a period of time:
Time_________________ Amount
t=0_____________________x
t=10,000 years____________x/2
t=20,000 years___________x/4
During the first 10,000 years the radioisotope lost half of its mass. After 10,000 years more (which means 2 half-lives), the remaining amount also lost half of its mass. Therefore, after 20,000 years, the we will have a fourth of the initial amount.
Hard water contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous ion may also be present;
<u>Explanation</u>:
- Hard water contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous ion may also be present; oxidized to the ferric form. It appears as a reddish brown stain on washed fabrics and enameled surfaces.
- Water hardness that is caused by calcium bicarbonates is known as temporary, because boiling converts the bicarbonates to the insoluble carbonates; hardness from other salts is called permanent.
- Calcium and magnesium ions in hard water react with the higher fatty acids off soap to form an insoluble gelatinous curd, thereby causing a waste of the soap.