Answer:
Answer: The mass of product left in the test tube will be less than the initial measured mass of the reactants.
Explanation: This is because one of the products of the reaction is a gas (hydrogen) and it escapes as the reaction happens in an open system.
This is the reaction,
Mg(s) + 2HCl(aq) --------> MgCl2(aq) + H2(g)
So, evidently, only MgCl2 is left in the reaction test tube together with unreacted reactants.
But, the hydrogen gas that escapes accounts for the lesser mass at the end of the reaction.
The mass in the test tube at the end of the reaction +
the mass of Hydrogen gas that escapes = the mass of reactants before the reaction; consolidating the law of conservation of mass.
The answer to this question is D. 3,2,3,2
Answer:
D. They are made of repeating subunits.
Explanation:
The first column represting polymers such as DNA, cellulose, nylon, hair are labelled with cells, plant material, synthetic material, animal material and They are made of repeating subunits.
<u>Not all the entries in the first column come from living things as nylon comes from synthetic material (man-made). But all four (DNA, cellulose, nylon, hair) are conists of repeating unit. </u>
DNA made up of nucleotides, cellulose is made up of rpeating units of monomer glucose, nylone is made of repeating unit of two monomers hexamethylene diamine and adipic acid, and hair is made of repeating unit of protein called keratin.
Hence, the correct answer is "D. They are made of repeating subunits."
We are going to use Avogadro's constant to calculate how many molecules of
carbons dioxide exist in lungs:
when 1 mole of CO2 has 6.02 x 10^23 molecules, so how many molecules in
CO2 when the number of moles is 5 x 10^-2
number of molecules = moles of CO2 * Avogadro's number
= 5 x 10^-2 * 6.02 x 10^23
= 3 x 10^22 molecules
∴ There are 3 x 10^22 molecules in CO2 exist in lungs