Chem Unit 1 & 2
Multiply the following three numbers and report with the correct number of significant figures. 1.60 * 10.52 * 150 = ?
2500
The measurement, 0.00206 g, has how many significant digits?
3
Add the following three numbers and report your answer using significant figures: 2.5 cm + 0.50 cm + 0.055 cm = ?
3.1
How many significant figures are in the following number?
6
What word did Democritus use for the atom, and what did it mean?
atomos - uncuttable
The atomic number is the number of...
protons
Multiply the following three numbers and report your answer to the correct number of significant figures 0.020 x 50 x 11.1 = ?
10
Subtract the following numbers and report your answer using significant figure 416 g - 210.05 g - 21.1 g = ?
185
How many meters is the average adult man
2 meters
Divide the following three numbers and report your answer to the correct number of significant figures 0.530 g / 0.1010 mL = ?
5.25
What is the difference between a theory and a law?
A theory is a set of ideas that tie together many observations. A law describes how some part of nature acts under certain conditions.
No matter which element Thomson put in a cathode ray tube, the same negative particles with the same properties (such as charge and mass) were ejected.
All atoms have electrons
After performing the gold foil experiment, Rutherford concluded that electrons are...
All located towards the very edge of the atom
Most of the alpha particles shot at the gold foil went straight through without being deflected.
Atoms are mostly empty space
A few of the alpha particles shot at the gold foil bounced straight back to where they were shot from.
Atoms contained a small dense center, called a nucleus
What did Aristotle believe matter was made from?
Earth, water, air, fire, ether
What part of the atom did J.J. Thomson discover with his cathode ray tube experiment?
Electron
Which subatomic particle has the least mass?
Electron
Which of the following best describes why Rutherford's gold foil experiment changed the model of the atom?
His experiment showed that the nucleus is small, dense, and positively charged. This was different from what the plum pudding model showed.
What quality of the theory of evolution makes it a theory?
It is the best explanation for why scientists have observed what they have
Cathode Ray Tube
JJ Thompson Electrons are negatively charged Neutral charge because there's a positive and negative
Changing the number of neutrons in an atom changes the atom's...
Mass number
How do you find density
Mass/volume
What is the charge and location of electrons in atoms?
Negative outside the nucleus
What is the charge and location of neutrons in atoms?
Neutral in the nucleus
What do all isotopes of the same element have in common?
Number of protons
What is the charge and location of protons in atoms?
Positive in the nucleus
An atom's identity is dependent on its number of...
Protons
The alpha particles (positively charged particles) were repelled by the nucleus. The nucleus contains protons and neutrons, and neutrons have a neutral charge.
Protons must be positive
Isotopes of elements have the same number of ____________ , and a different number of ___________ .
Protons, neutrons
Indicate the number of protons, neutrons, and electrons in the following isotope: boron-11
Protons: 5 Neutrons: 6 Electrons: 5
Indicate the number of protons, neutrons, and electrons in the following isotope: 9 19F-
Protons: 9 Neutrons: 10 Electrons: 10
Gold foil experiment
Rutherford Nucleus is positiviely charged, dense, and small Atoms are mostly empty space
What are the two criteria for a scientific hypothesis?
Testable and falsifiable
What is the difference between atomic mass, atomic number, and mass number?
The atomic mass is the weighted average of the isotopes, the atomic number is the number of protons, and the mass number is neutrons plus protons
Particles ejected in the cathode ray tube experiment bent away from the negatively charged plate, and towards the positively charged plate.
The ejected particles (electrons) were negatively charged
Some alpha particles (with positive charges) shot at the gold foil were deflected, and bent away from the foil.
The nucleus is positively charged
Which of the following is TRUE about a neutral atom?
There are equal numbers of protons and electrons
J.J. Thomson discovered the electron, and found its charge using charged plates. Which of the following best describes the path the electrons took in Thomson's experiment?
Towards the positive plate
What was daltons theory?
all matter is made up of individual particles called atoms, which cannot be divided. All atoms of the same element are identical. Atoms can't be create or destroyed.
Changing the number of electrons in an atom changes the atom's...
charge
If an atom loses an electron, how does its net charge change?
increases, becomes more positive
The mass number is the number of
protons plus neutrons
An element's atomic mass is the...
weighted average mass of all the isotopes of the element