Test Review Flashcards
“Gold melts at a high temperature” is a ___________ property. Explain your reasoning.
Physical because melting is a change in state and doesn’t create a new substance.
The density of zinc is 7.14 g/mL” is a ____________ property. Explain your reasoning.
Physical. Density is determined by comparing mass and volume. This does not change the substance.
Digesting a sandwich is a _______________ change. Explain your reasoning.
chemical because a new substance is formed.
Boiling alcohol is a _______________ change. Explain your reasoning.
Physical. It doesn’t change substances only states when boiled.
Is a cup of tea a pure substance, a mixture, an element or a compound? Explain your reasoning.
It’s a mixture of water, tea leaves and often milk and sugar. Even though they may be dissolved the are still distinct substances and have not bonded.
Is mineral water a homogeneous or heterogeneous mixture?
homogeneous mixture
Is hydrochloric acid, HCl, an element or a compound?
Compound
What do we study when we study chemistry?
Matter
In a Physical change
No new substance is formed
In a Chemical change
New substances formed
What is an atom
Smallest particle of element.
Define element?
An element is a substance consisting of atoms which all have the same number of protons - i.e. the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical methods.
What is a molecule?
Two or more atoms bonded together?
What is molecule of an element?
Two or more molecules of same element bonded together.
Define molecule of the compound
Two or more different atoms bonded together.
Define Pure substance
Contains only 1 type of particle.
Define mixture
Two or more substances that are mixed but not bonded.
Define Homogenous mixture (solution)
No individual substances identifiable. Equal distribution of particles ex coffee
Define heterogeneous mixture
Unequal distribution of particles
More than one phase.
Ex salad, oil and water
Element, compound or mixture? Why?
Sugar dissolved in water (H2O)
Homogenous mixture. Because it is equal distribution of particles and 2 or more elements mixed together but not bonded.
Element, compound or mixture? Why?
Gold
Element since it is found on the Periodic Table and only has one type of atom.
Element, compound or mixture? Why?
Magnesium chloride.
Compound because 2 or more different atoms are bonded together.