Well the answer to number 1 is definitely B
number 2 is B
number 3 is D
Number 4 is C
Hope this helps:)
Explanation:
Significant figure is the measure of how accurately something can be measured. It carries meaning contributing to its measurement resolution. It is important to use proper number of significant figures to get a precise measurement. For example, if we use a meter stick then measurements like 0.874 meters, or 0.900 meters, are good because they indicate that we can measure to the nearest millimeter. Whereas a measurement like 0.8 does not tell that a meter stick can measure to the nearest millimeter.
Answer:
Common combustion reactions break the bonds of hydrocarbon molecules,
Explanation:
the resulting water and carbon dioxide bonds always release more energy than was used to break the original hydrocarbon bonds. That's why burning materials mainly made up of hydrocarbons produces energy and is exothermic.
Answer:

Explanation:
Given that,
The distance between the centers of the two oxygen atoms in an oxygen molecule is
.
We need to convert this distance in inches.
We know that,
1 cm = 0.393 inches
We can solve it as follows :

So, the distance between the centers of the two oxygen atoms is
.
Answer:
"500 Joule/sec" is the right answer.
Explanation:
The given values are:
Force,
F = 1000 N
Velocity,
s = 10 m
Time,
t = 20 s
Now,
The power will be:
= 
On putting the values, we get
= 
= 
= 