Acidic. An increase in the amount of H+ ions indicates an acid solution.
1.506 × 10²³ carbon atoms
Explanation:
First we calculate the number of moles of calcium carbonate (CaCO₃) contained in 25 g.
number of moles = mass / molecular weight
number of moles of CaCO₃ = 25 / 100 = 0.25 moles
Now we make use of Avogadro's number which tell us that we have 6.022 × 10²³ molecules (or atoms) in one mole of substance.
Now in our case:
if in 1 mole of CaCO₃ we have 1 × 6.022 × 10²³ carbon atoms
then in 0.25 moles of CaCO₃ we have X carbon atoms
X = (0.25 × 1 × 6.022 × 10²³) / 1
X = 1.506 × 10²³ carbon atoms
Learn more:
Avogadro's number
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Answer: A. the variable that is changed on purpose in an experiment.
Answer:
Modern scientists base their classifications mainly on molecular similarities. They group together organisms that have similar proteins and DNA. Molecular similarities show that organisms are related. In other words, they are descendants of a common ancestor in the past.
Explanation:
Speed of light = freq * wavelength
<span>wavelength = speed of light / freq = (3*10^8 m/sec ) / (2.6 * 10^9 /sec) = 1.15 * 10^(-1) m </span>
<span>1.15 * 10^(-1) m *(10^9 nm / m) = 1.15 * 10^8 nm</span>