The answers are
The age of the oldest stars
How fast distant galaxies are moving away from us
Patterns of background radiation.
Explanation:
The Astronomers calculate the age of the universe by looking for oldest stars, and by measuring the rate of expansion of the universe and back to big bang.
The Astronomers used the techniques like the age of oldest stars, how fast the distant galaxies are moving away from us, patterns of background radiation and along with the Big Bang as reference point, they estimate that the universe may be approximately 12 billion years old.
<u>Answer:</u> The mass of solution having 768 mg of KCN is 426.66 grams.
<u>Explanation:</u>
We are given:
0.180 mass % of KCN solution.
0.180 %(m/m) KCN solution means that 0.180 grams of KCN is present in 100 gram of solution.
To calculate the mass of solution having 768 mg of KCN or 0.786 g of KCN (Conversion factor: 1 g = 1000 mg)
Using unitary method:
If 0.180 grams of KCN is present in 100 g of solution.
So, 0.768 grams of KCN will be present in =
of solution.
Hence, the mass of solution having 768 mg of KCN is 426.66 grams.
Answer:
The advantages described below
Explanation:
Advantages of a balanced chemical equation versus word equation:
- easier to read: chemical equations typically only take one line and they include all the relevant information needed. They are short-hand notations for what we describe in words.
- balanced chemical equations show molar ratio in which reactants react and the molar ratio of the products. Those are coefficients in front of the species. This is typically not included in a word equation, for example, hydrochloric acid reacts with potassium hydroxide. The latter statement doesn't describe the molar ratio and stoichiometry.
- includes relevant information, such as catalysts, temperature and pressure above the arrow in the equation. We wouldn't have this in a word equation most of the time.
- shows the stoichiometry of each compound itself, e. g. if we state 'ammonia', we don't know what atoms it consists of as opposed to
. - includes states of matter: aqueous, liquid, gas, solid. This would often be included in a word equation, however.
The answer is B chlorine. Chlorine is and elements and the others are compounds.
Roughly 19,089,294,774,226,281 years