A. Relative abundance
B. Average mass of element
C. Number of isotopes
D. Relative isotopic mass
A. Atomic number
B. Relative abundance
C. Electronic configuration
D. All of the above
A. 0.2m
B. 0.2mm
C. 0.2nm
D. 0.2pm
A. Paint
B. Glass
C. Gun Powder
D. Cement
Covalent network crystals have_____________?
A. higher melting point then molecular crystals
B. lower melting point then molecular crystals
C. discrete molecules linked by Van der waals forces
D. hydrogen bonding
All of the following substances are crystalline except_____________?
A. Ice
B. Diamond
C. Sucrose
D. Plastic
Some substances are good conductor of electricity in both the solid and liquid states. These substances are generally______________?
A. ionic substances
B. metallic substances
C. molecular solids
D. covalent network solids
Which of the following is a substance?
A. Sea water
B. Brass
C. Tape water
D. Graphite
E. Sand
In chemistry, a substance refers to a matter which has specific composition and specific properties which do not change. A substance can be an element or a compound. A substance typically has a constant composition, which can not be separated by physical methods. Seawater and sand are not substances, because they have varied compositions and their components can be separated by physical methods.
Sodium carbonate is produced by____________?
A. haber process
B. Amonia solvay process
C. decons process
D. lead chamber process
Electron was discovered by?
A. Michael Faraday
B. James Maxwell
C. Yuri Gagarin
D. J.J Thomson