Answer:
Percent error = 1.5%
Explanation:
Given data:
Measured value of density of graphite = 2.3 g/cm³
Percent error = ?
Solution:
Formula:
Percent error = [Measured value - Actual value / actual value] × 100
Actual/accepted value of density of graphite = 2.266 g/cm³
Now we will put the values:
Percent error = [2.3 g/cm³ - 2.266 g/cm³ / 2.266 g/cm³] × 100
Percent error = [0.034 g/cm³ / 2.266 g/cm³] × 100
Percent error = 0.015 × 100
Percent error = 1.5%
The correct option is B.
Stars live out most of their lives at MAIN SEQUENCE. Stars generally are divided into three major stages, these are:
1. Pro stars and pre-main sequence star
2. Main sequence and giant star
3. Variable stars
Major stages in the life of a star can last for millions of years.
Nitrous Acid.
Hyponitrous acid: H2N2O2
Nitric acid: HNO3
Pernitric acid: HNO
Answer : The correct option is, (2) Energy is absorbed as bonds are broken.
Explanation :
As we know that the bonds are formed and breaks during the chemical reaction. Some energy is released or absorbed when the bonds are formed and breaks during the chemical reaction.
During the bond breaking, some energy is required to break the bonds.
During the bond formation, some energy is released to the formation of the bonds.
In the given reaction, the bond between the hydrogen-hydrogen in 
are breaking into two hydrogen. That means during the bond breaking, some energy is required or absorbed to break the bonds.
Hence, the correct option is, (2) Energy is absorbed as bonds are broken.
Answer:
Cheap energy
Explanation:
Fossil fuels such as coal, oil, and gas are widely available and are much cheaper than other forms of energy (wind, nuclear, etc.) Fossil fuel products are also quite efficient, as the efficieny of fossil fuels is about 50% (which is actually really good), while solar panels for example are only about 15% efficient.
