Law of Conservation of Mass
This scientific law states that matter cannot be created or destroyed in a chemical reaction.
What is the Law of Conservation of Mass?
This scientist proposed that atoms were solid spheres with no internal structure.
Who was John Dalton?
This scientist proposed that electrons orbit the nucleus in fixed energy levels.
Who was Niels Bohr.
This subatomic particle has a positive charge.
What is a proton.
This is the name of the small number written low in a chemical formula that shows how many atoms of an element are present.
What is a subscript.
This type of substance has a pH less than 7.
What is an acid.
In a closed system, this value must remain the same before and after a chemical reaction.
What is the total mass?
Dalton believed atoms of the same element shared this property.
What is “they are identical” or "same"?
In Bohr’s model, electrons can only exist in these specific paths around the nucleus.
What are energy shells.
This particle has no charge and is found in the nucleus.
What is a neutron.
This is the only number you are allowed to change when balancing equations.
What is the coefficient.
This type of substance has a pH greater than 7.
What is a base.
When vinegar reacts with baking soda in an open container, the mass appears to decrease because this escapes.
What is carbon dioxide gas?
This model described the atom as a positively charged ball with electrons embedded inside it.
What is Thomson’s Plum Pudding Model?
Bohr said electrons do this when they absorb or release energy.
What is jump between energy levels.
This negatively charged particle moves rapidly around the nucleus.
What is an electron.
In the equation H₂ + O₂ → H₂O, this element is unbalanced.
What is oxygen.
This ion is found in all acids.
What is H⁺ (hydrogen ion).
This type of container is required to accurately demonstrate the Law of Conservation of Mass.
What is a closed system (sealed container)?
Thomson discovered this negatively charged subatomic particle.
What is the electron?
This is the maximum number of electrons that can fit in the first Bohr shell.
What is 2.
This number tells you how many protons an atom has.
What is the atomic number.
The balanced form of H₂ + O₂ → H₂O.
What is 2H₂ + O₂ → 2H₂O.
This ion is found in all bases.
What is OH⁻ (hydroxide ion).
If 25 g of reactants produce 10 g of one product, this is the mass of the remaining product.
What is 15 grams?
Rutherford’s gold foil experiment showed that atoms are mostly this.
What is empty space?
This is the maximum number of electrons that can fit in the second Bohr shell.
What is 8.
This value is calculated by adding protons and neutrons together.
What is the atomic mass (mass number).
This is the first step when balancing any chemical equation.
What is count the atoms on each side.
This scale is used to measure how acidic or basic a substance is.
What is the pH scale.