Answer:
4.083 * 10^20 atoms.
Explanation:
One Mole of phosphorus contains 6.022 * 10^23 atoms (Avogadros number)'
Since 1 mole of Phosphorus has a mass of 30.974 grams, 21 milligrams has
6.022 * 10^23 * 0.021 / 30.974
= 0.004083 * 10^23
= 4.083 * 10^20
Here are the answers in order:
1. During a physical change the substance changes physically.
2. The law of conservation of mass is a law stating the conservation of mass cannot be higher than 46mg or lower than 32mg.
3. A hypothesis is a guess that you make before completing a science experiment, it can be considered a law because it is important to know why you are making the guess.
4. During a chemical change the mass is changing colors. This is a representation of a chemical change.
5. Oil is a non-renewable resource, so it cannot demonstrate the conservation of mass.
6. When the color of the substance has changed or when it explodes.
7. Reactants are the objects that react when in a chemical change.
8. If you follow the rule of not going higher than 46mg and not lower than 32mg then it will automatically follow this law.
Chemical Reactions Part One Video:
1. mass
2. erupt-ant
3. reactant
4. object
5. mixtures
6. molecules
7. color changed
Questions again:
1. A chemical reaction
2. A physical change
3. Because if it is no higher than 46mg and no lower than 32mg then it will follow on it's own.
Answer:
5.8 g
Explanation:
Molecular weight in Daltons is equivalent to the molecular weight in grams per mole.
The amount of NaCl required is calculated as follows:
(2 mol/L)(50 mL)(1 L/1000 mL) = 0.1 mol
This amount is converted to grams using the molar mass (58 g/mol).
(0.1 mol)(58 g/mol) = 5.8 g
Answer:
c.
Explanation:
One of the main differences between an atom and an element is that an atom can be combined but an element cannot be combined. There are many combinations of atoms that make up different gases, liquids, and solids each with a unique makup. For example, water is made up of two hydrogen atoms and one oxygen atom (H20). Elements are made up of only the same type of atom. For example, the element Hydrogen can only contain hydrogen atoms, while the element Carbon can only contain carbon atoms.
