We know that it is a certainty based on things such as the size, mass, brightness, etc. They can determine to within a relative level of accuracy the age. Of course they can be off by millions of years, but that’s pretty precise for a 10–20 billion year time period for the life of a star. BUT we absolutely cannot predict exactly when it will explode and we see supernovas in other galaxies, but the last one in the Milky Way that we observed was in the 1600s.
Let's examine the given choices:
V = (4/3)*pi*(r)^3 is the rule to calculate the volume of the sphere
V = (1/3)*pi*(r)^2*h is the rule to calculate the volume of the cone
V = s^3 is the rule to calculate volume of the cube
V = pi*(r)^2*h is the rule to calculate volume of the cylinder
Now, the ball can be treated as a perfect sphere, therefore, to calculate its volume we will use the rule of the volume of sphere.
Based on this, the correct choice is:
V = (4/3)*pi*(r)^3
Convert all the gases from grams to moles using their molar masses first. Remember that nitrogen and oxygen exist as DIATOMIC gases.
O2 - 25 g / 32 g/mol = 0.78 mol O2
N2 - 15 g / 28.02 g/mol = 0.54 mol N2
He - 10 g / 4.0 g/mol = 2.5 mol He
Add all the moles of gases.
0.78 + 0.54 + 2.5 = 3.82 moles
Divide O2 moles by total moles.
0.78/3.82 = 0.20
Answer:
The correct answer is option b.
Explanation:
Mass of coal burned = 
metric ton = 1.00\times 10^6\times 10^3 kg=10^9 kg[/tex]
1 metric ton = 
Molar mass of coal :
1 g = 0.001 kg
Moles of coal ,n :
If 2 moles of coal on combustion gives 270 moles of carbon dioxide than n moles of coal will give;
of carbon dioxide.
Molar mass of carbon dioxide gas = 44 g/mol = 0.044 kg/mol
Mass of 
of carbon dioxide:
Answer:
1. Diazonium salt
2. Coupling component
Explanation:
Azo dyes re synthesized by the combination of two organic compounds viz
1. Diazonium salt
2. Coupling component
1) For methyl red, the diazonium salt which is an intermediate product is produced by the reaction of hydrochloric acid (HCL) with anthranilic acid and sodium nitrate (NaNO₂)
2) The produced diazonium salt is then combined with dimethylaniline which is a coupling component rich in electrons to undergo a chemical reaction that by an aromatic substitution mechanism to produce methyl red as the final product.
