SCIENCE Flashcards
What is the difference between physical and chemical properties?
Chemical: a substance’s ability to change into a new substance with different properties, Physical: is properties that can be observed and measured without changing the identity of the substance.
What is a pure substance?
A sample of matter that has specific chemical and physical properties.
What is the name given to a large molecule that is made up of smaller molecules and an example?
A macromolecule, DNA
What is a chemical bond?
The attractive force that holds things together.
Compare and contrast elements and compounds.
ELEMENT:is a pure substance that can not be separated by chemical means.COMPOUND: A pure substance made up of two or more different types of chemical bonds.
How is the periodic table organized?
It is organized by rows called periods and columns called groups according to increasing atomic number. There are 18 groups.
Matter is a word that is used to describe what?
Physical things.
What do scientists use to represent molecules, cells and other structures or planets and the solar system?
models.
Compare and contrast weight and mass?
Weight is the measure of gravitational force on an object,the greater the mass on an object the greater the gravitational pull(weight), Mass is the measure of the amount of matter in an object, more matter = more mass.. Weight is measured in pounds and mass is measured in grams.
Compare and contrast density and volume.
Density is the ratio of mass to volume, more mass means more density, volume is how much space something occupies.
What tells us that pure chemical compounds always contain the same elements in exactly the same proportions by mass?
The law of definite proportions
When two or more elements combine to form a new substance, what are the properties of the new substance in relation to combining elements?
The properties will be different from the combined elements.
What is the relationship between atoms, substances, and ratios?
The atoms of a particular substance is always going to combine in a fixed ratio.
