Question

quiz 8.6be- counting atoms, chemical equations and the law of conservation of mass
use the periodic table to identify the types of atoms and quantities of each in the following chemical formula.
2ch₄
calcium - 2
○ hydrogen - 4

carbon - 1
○ hydrogen - 8

carbon - 2
○ hydrogen - 8

carbon - 2
○ hydrogen - 4

Explanation:

Step1: Analyze the chemical formula \(2CH_4\)

In the formula \(CH_4\), there is 1 carbon (C) atom and 4 hydrogen (H) atoms. The coefficient 2 in front of \(CH_4\) means we have 2 molecules of \(CH_4\).

Step2: Calculate the number of carbon atoms

For carbon: \(1\times2 = 2\) carbon atoms.

Step3: Calculate the number of hydrogen atoms

For hydrogen: \(4\times2 = 8\) hydrogen atoms.

Now let's check the options:

• First option: Calcium is not in \(CH_4\), so incorrect.
• Second option: Carbon should be 2 (not 1) and hydrogen should be 8 (not 8? Wait, no, carbon is 1 here which is wrong), so incorrect.
• Third option: Carbon - 2 (correct, \(1\times2 = 2\)) and hydrogen - 8 (correct, \(4\times2 = 8\)), this matches.
• Fourth option: Hydrogen is 4 which is wrong (should be 8), so incorrect.

Answer:

carbon - 2
hydrogen - 8 (the option with carbon - 2 and hydrogen - 8)