Answer:
Radium is used to produce Radon
Explanation:
Radon is a gas used to treat cancer (certain types).
Answer:
Have high melting points and high boiling points.
Explanation:
- Covalent bonds are types of chemical bonds that result from the sharing of electrons between non-metal atoms.
- Covalent bonds result in the formation of covalent compounds.
- Covalent compounds are characterized by low melting and boiling points.
- Therefore, it won't be true to say they have high melting and boiling points.
- Other properties of covalent bonds include poor conductors of electricity and heat, gases or liquids at room temperature, and are non-polar compounds among others.
Answer:

=> The colour of this stone is usually a pale greenish blue, owing to the presence of iron impurities. Stones that are treated with heat look more blue than green. On the Mohs scale of hardness, aquamarine ranges between 7.5 and 8 making it a relatively hard gemstone.
=> The best way to identify a real aquamarine stone is by looking at its colour. In its natural form, they have a pale blue colour, which is similar to seawater. They may have a slight green or yellow tint as well. Naturally occurring gems have excellent clarity and transparency.
=> The hardness of the stone is another feature you can use to identify the stone. Aquamarine stones are hard and they don’t get scratches easily. However, they can easily scratch glass and other such surfaces. So, if you find visible scratches on the stone, rethink your decision to buy it.
=> Most faceted aquamarine stones are clean to the eye and clear of any inclusions. However, translucent and opaque aquamarine is also available. These are usually fashioned into cabochons or beads. In some cases, inclusions may appear as parallel tubes. Such stones can be crafted to show a cat’s eye. Stones with cat’s eye and star effect are rare and highly priced.
Answer:
36
Explanation:
products and reactants have to be equal
Answer:
Melting of ice
Explanation:
A physical change is one in which just the physical properties of the matter is altered. Most phase changes reaction falls under this type of change.
- Examples are boiling, melting, freezing, condensation, sublimation, magnetization of metals, breaking glass, cutting wood.
- No new kinds of matter is formed.
- The process is reversible
- No change in mass