Answer:
A. 97.8 mm
Explanation:
There are 10 divisions between 9 cm (90 mm) and the end of the ruler (10 cm or 100 mm).
Each division equals 1 mm.
Each 5 mm mark has a longer tick, and the dashed red line is between the 97 mm and 98 mm marks.
You would normally estimate to the nearest tenth of a division. An estimate of 0.8 mm is reasonable.
The length of the object is 97.0 mm + 0.8 mm = 97.8 mm.
B is wrong. You can't possibly estimate to the nearest hundredth of a division.
C is wrong. The dashed red line slightly before the 98 mm mark.
D is wrong. If the dashed red line were exactly on the 98 mm mark, you would record the measurement as 98.0 mm. This indicates that you measured the object to zero tenths on either side of the mark.
Carbon is the only nonmetal
Speed=distance/time
D=150km
S=7200s
Divide the numbers.
150/7200=0.02km/s <---final answer
The reaction for burning of charcoal or complete combustion is as follows:
From the above balanced reaction, 1 mole of carbon releases 1 mole of 
gas.
Converting mass of charcoal into moles as follows:
Molar mass of pure carbon is 12 g/mol thus,
The same moles of is released. Converting these moles into mass as follows:
m=n×M
Molar mass of is 44 g/mol thus,
Converting mass into kg,
Thus, total mass of gas released is 5.5 kg.
The Answer for this question is : A
1 & 2
