chem unit 1

Significant Figures (Sig Figs)

Digits that carry meaning contributing to their measurement accuracy.

Which integers always count as significant figures?

Nonzero integers always count.

What do leading zeros do in significant figures?

Leading zeros do not count.

Do sandwich zeros count in significant figures?

Yes, sandwich zeros count.

When do trailing zeros count as significant figures?

Trailing zeros don’t count unless there is a decimal.

What do exact numbers do to significant figures in an answer?

Exact numbers do not limit the number of sig figs in the answer.

When multiplying or dividing, how do you determine the number of significant figures in the result?

Use the same number of sig figs as the number with the fewest sig figs.

In addition or subtraction, how are decimal places in the result determined?

The result must have the same number of decimal places as the measurement with the fewest decimal places.

What should the answer's trailing zeros reflect in addition/subtraction?

The answer should have the same number of trailing zeros as the measurement with the most trailing zeros.

What is the conversion factor for moles?

1 mole = 6.02 x 10^23.

What does the mnemonic 'Kangaroos Hopped Down Black Dark Caves, Making Mysterious Noises' help remember?

It aids in recalling the order of operations for dimensional analysis.

What are the steps to balance a chemical reaction?

Count atoms, balance one element at a time, revisit others, and double-check.

Where are reactants located in a chemical equation?

Reactants are on the left side.

Where are products located in a chemical equation?

Products are on the right side.

What are coefficients used for in chemical equations?

Coefficients are used to balance the equation and represent the number of moles.

What should you do to ensure your chemical equation is balanced?

Balance the atom counts and check your work.

How do you reduce coefficients in a balanced equation?

Reduce coefficients to the lowest whole numbers.

What color change occurs when acids are present?

Blue to red for acids.

What color change occurs when bases are present?

Red to blue for bases.

What phrase is used to remember that acids 'turn angry'?

Acids turn angry.

What are leading zeros in significant figures?

Zeros before the first nonzero digit that do not count.

What are trailing zeros in significant figures?

Zeros after the last nonzero digit that count only if there is a decimal.

What is dimensional analysis used for?

Converting units to different measurement systems.

How does one balance the equation for a chemical reaction?

Check that atom counts match on both sides.

What happens when the coefficients in a chemical reaction are balanced?

The moles of each substance involved are correctly represented.

What indicates a successful balance in a chemical equation?

The number of atoms of each element is the same on both sides.

What is the first step in balancing a chemical equation?

Count atoms of each element.

What should be checked after balancing a chemical equation?

Revisit other elements and double-check your work.

Which significant figures rule applies to addition and subtraction?

The result must align with the measurement having the fewest decimal places.

What do coefficients provide in chemical reactions?

They indicate the mole ratio for reactants and products.

What is a characteristic of exact numbers?

They do not affect the significant figures of the final answer.

What is important about the coefficients in terms of whole numbers?

They should be reduced to the lowest whole numbers possible.

What does the term 'sandwich zeros' refer to?

Zeros that are between nonzero digits and count towards significant figures.

What are the two types of quantities in dimensional analysis?

Base quantities and derived quantities.

What mnemonic can help remember the balancing process for chemical reactions?

Cats Bring Rice Dishes.

In significant figures, what counts as a zero?

Only the zeros that are deemed significant based on their placement.