Chemistry Unit 1 test Flashcards
What is an allotrope
One or more forms of an element that can exist in the same physical state
What is a physical change
When the identity of a substance says the same but something physical of the object may change
What is a chemical change
When the identities of a substance change & a new substance forms
Equation for density
density = m/v
Equation for Volume
Volume = m/d
Equation for mass
Mass = d/v
What is a pure substance?
A pure substance is a sample of matter that has definitie chemical and physical properties
What is a heterogenous mixture
They have visually distinguishable components, not mixed
What is a homogenous mixture?
They have a uniform throughout look
How are the particles in a solid
Packed together and unable to move
How are the particles in a liquid
In a liquid the molecules are able to move around one another but still relatively close together
How are the particles in a gas
In a gas the molecules are spread out & move freely
Examples of allotropes?
O2 & O3 are allotropes for Oxygen
Example of a physical change?
Crushing a rock, dissolving sugar, changing location, arrangement, or speed
Example of chemical changes?
mercury (II) oxide (arrow) mercury + oxygen
baking a cake, burning wood
What is an endothermic process?
When it absorbs energy
Exothermic process
releases energy
Accuracy vs Precision
Accuracy is how close it is to the true value, precision is when the estimate values are close togheter
