Answer:
Land fill
Explanation:
A landfill is a carefully managed waste disposal site. It is the oldest method of waste disposal. In a dumpsite, biodegradable materials decay overtime.
However, non-biodegradable materials such as plastics and other polymers tend to last many years in landfills. This category of wastes pose a great threat to the environment.
Answer:
19656J
Explanation:
Step 1:
Data obtained from the question.
Mass (M) = 78g
Initial temperature (T1) = 20°C
Final temperature (T2) = 80°C
Change in temperature (ΔT) = T2 – T1 =
80°C – 20°C = 60°C
Specific heat capacity (C) = 4.2J/g°C
Heat (Q) =...?
Step 2:
Determination of the heat required for the reaction.
Q = MCΔT
Q = 78 x 4.2 x 60
Q = 19656J
Therefore, 19656J of heat is required.
Answer:
C and D
Explanation:
Atoms with five, six or seven valance electrons gain electrons to complete the octet because it is more convenient for the atoms to gain three, two or one electron as compared to lose five, six or seven electrons. Thus atoms with five, six or seven valance electrons form negative ions by gaining electrons.
Atoms with one, two or three valance electrons lose the electrons to get complete octet because it is more convenient for the atoms to lose one two or three electrons as compared to gain the seven, six or five electrons. The atoms with one, two or three valance electrons form positive ions.
Answer: 4 A1+3 02 → 2 Al2O3
Explanation: Two different atoms combines together to produce a compound.
