Science and Matter (CHEM CH 1/2)

A chemical change happens when...

• a substance is changed at the atomic level 
• bonds are broken and formed 
• a new substance is made
• all of the above! 

What kind of change is a phase change?

• Physical - it's still the same substance
• chemical - it's made of chemicals 

The compounds or elements present at the end of a reaction 

• reactants
• catalyst
• products
• energy 

The compounds and elements that are present at the beginning of a reaction:

• reactants
• catalyst
• products
• energy 

What does it mean when we say 'mass is conserved'?

• A measure of how much mass is created or destroyed. 
• Mass can neither be created nor destroyed during a chemical reaction. 

How does the "transfiguratoin" of a cat into a professor violate the idea of conserving mass?

• Mass can neither be created nor destroyed. 
• About 100 pounds are lost or gained on the transfiguration 
• Either the cat would have to be 110 pounds, or the person 10 pounds
• all of these 

To notice for a scientific purpose

• Question
• Conclusion
• Observe
• Classify

A testable prediction about a scientific investigation

• Question
• Observation
• Hypothesis
• Experiment

A decision based on facts you have discovered

• Conclusion
• Collaborate
• Prediction
• Results

A test or trial to discover something unknown

• Data
• Question
• Experiment
• Hypothesis