Experimental Design & Properties of Water U1 Flashcards
What is a hypothesis?
A testable explanation or prediction based on the observation and the scientist’s prior knowledge
What is a null hypothesis?
A prediction that there is no relationship between two variables.
What is an independent variable?
The factor or condition being changed“the cause”X-axis
What is a dependent variable?
The factor or condition being measured“the effect”Y-axis
What is a control variable?
A factor or condition that is keptconstant throughout the experiment
What is a control group?
This group experiences the sameconditions as the experimental group,except for the single independentvariable being studied
What is a controlled experiment?
done in lab
What is a natural experiment?
observing andanalyzing something happeningnaturally, out of control of the scientist
What is quantitative data?
Based on numbers
What is Qualitative data?
Based on Observation
What is an atom?
the basic unit of matter.
What is an element?
a pure substancethat consists of one type ofatom.
What is an atom composed of?
Atoms are composed of threesubatomic particles:
What is a Proton?
Positively charged subatomic particle, found inthe nucleus.
What is a Neutron?
Subatomic particle with no charge, found inthe nucleus.
What is an electron?
Negatively charged subatomic particle, foundoutside of the nucleus.
What are the first 3 layers of electron shells made of?
1st Orbital: Maximum 2 electrons2nd Orbital: Maximum 8 electrons3rd Orbital: Maximum 18 electrons
What is an atomic number?
the number of protons in the atom.
What is a mass number?
the total number of protons and neutrons inthe nucleus of an atom.
What is atomic weight?
the weighted average of the masses of anelement’s isotopes.
What is an isotope?
Atoms off the same element that differ in the numbers of neutrons they contain. Identified by mass number.
What is a valence shell?
the outer orbital/electron shell.
What is a cell?
basic unit of life
What is a compound?
a substance formed by the chemical combination of two or more elements in definite proportions.
What is a molecule?
made when two or more atoms are chemically bonded together?
What are the two types of chemical bonds?
Ionic and Covalent
What are ionic bonds?
Chemical bond formed when one or moreelectrons are transferred from one atom to another.
What is an ion?
An atom that either gains electrons or loses electrons.As such, it is either positively or negatively charged.
What are covalent bonds ?
Chemical bond formed when the electronsare shared between atoms.
What do carbons four valence electrons allow them to do?
bond with many otheratoms. As such, chains of carbon often formthe backbone of macromolecules.
What are macromolecules?
Macromolecules are largemolecules made frommany smaller molecules.
What are Monomers and Polymers?
Monomers: the small units.* Polymers: the large units.
What is polarity in a hydrogen molecule?
a water moleculeis polar because there isan uneven distribution ofelectrons between thehydrogen atoms andoxygen atoms. Thenegative pole is near theoxygen atom and thepositive pole is near thehydrogen atoms
What are Intramolecular forces?
forces that holdatoms together withina molecule.
What are Intermolecular forces?
forces that existbetween molecules.
what is a hydrogen bond?
attraction between ahydrogen atom andanother atom.
What is cohesion and adhesion?
attraction of molecules of the same substance.attraction between molecules of different substances.
What is Capillary Action?
tendency of water to rise in a thin tube.
What is a mixture?
a material composed of two or more elements orcompounds that are physically mixed together but not chemicallycombined.
What is a suspension?
mixture of water and nondissolved material
What is a solution?
type of mixture in which all components are evenlydistributed
What are solutes and solvents?
Solute: substance that is dissolved in solution. Ex: sugar,saltSolvent: dissolving substance in a solution. Ex: water
What is hydrophobic?
nonpolarmolecules that repel watermolecules. “Water fearing”
What is hydrophilic?
molecules formingionic or a hydrogen bond withwater molecules. “Waterloving”
What is surface tension?
The surface becomes stronger because they exert more force horizontally when they cant exert it up(happens to water)
