Answer:
polyatomic, ionic
Explanation:
unit that contains two or more atoms covalently bonded together but that has an overall charge is called a(n) polyatomic ion. Many ionic compounds contain such units.
Answer:
4.5 kilograms of silicon dioxide is required to produce 3.00 kg of SiC.
Explanation:
The balanced equation for the reaction between silicon dioxide and carbon at high temperature is given as:

1 mole silicon dioxide reacts with 3 moles of carbon to give 1 moles of silicon carbide and 2 moles of carbon monoxide.
Mass of SiC = 3.00kg = 3000.00 g
1 kg = 1000 g
Molecular mass of SiC = 40 g/mol
Moles of SiC = 
According to reaction, 1 mole of SiC is produced from 1 mole of silicon dioxide.
Then 75 moles of SiC will be produce from:
of silicon dioxide.
mass of 75 moles of silicon dioxde:

4.5 kilograms of silicon dioxide is required to produce 3.00 kg of SiC.
Answer: Galaxy
Explanation: A galaxy is a large system of stars held in place by mutual gravitation.
Explanation:
When conducting a melting point experiment, if we were to heat a sample quickly. Large amount heat is provided instantly which would melt the crystals in the tube very quickly, even before the temperature of the thermometer reaches to that level. So the observes melting point would be much lower than the actual melting point when sample is heated slowly.