To find the answer you can set up an equation like this: 3(x)(d)
x would stand for number of cans each dog eats, while d stands for the number of days in a week. 3(2)(7)=42 Sam would have to purchase 42 cans of dog food each week.
Physical change can change a substance by affecting the form of a chemical change.
Examples of physical changes:
Something cut (Paper)
Molded (Bread)
Boiled (Water)
Mixed (Berries and strawberries)
HOPE THIS HELPS YOU! ^_^
Answer: The coefficient of nitrogen in the given equation is 2.
Explanation: The reaction for the oxidation of methamphentamine with oxygen gas in the body is given by:

By Stoichiometry,
4 moles of methamphentamine reacts with 55 moles of oxygen gas to produce 40 moles of carbon dioxide gas, 30 moles of water and 2 moles of nitrogen gas.
Coefficient of 
Coefficient of 
Coefficient of 
Coefficient of 
Coefficient of 
Hence, the coefficient of nitrogen in the given equation is 2.
Answer:
Explanation:
1) Valence electrons
2) Electrons
3) 2 electrons on K-shell
4) 8 electrons on L-Shell
5) 18 electrons on M-shell
6) nucleus
7) Proton
8) neutron
9) principal energy level
10) atomic number
11) symbol of the atom
12) name of the atom
13) atomic mass
Answer:
- <u>You need to convert the number of atoms of Ca into mass in grams, using Avogadro's number and the atomic mass of Ca.</u>
Explanation:
The amount of matter is measured in grams. Thus, you need to convert the number of atoms of Ca (calcium) into mass to compare with 2.45 grams of Mg.
To convert the atoms of calcium into mass, you divide by Avogadro's number, to obtain the number of moles of atoms, and then divide by the atomic mass of calcium.
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<u>1. Number of moles, n</u>

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<u>2. Mass</u>
- mass = number of moles × atomic mass
- mass = 0.053969mol × 40.078g/mol = 2.16g
Then, 2.45 g of Mg represent a greaer mass than the 3.25 × 10²² atoms of Ca.