The Scientific World
A repeated observation that summarizes a natural pattern and can be used to make predictions is called this.
What is a Scientific Law?
Express 0.0007080 in scientific notation.
7.080×10−4
Anything that has mass and occupies space is known by this term.
Matter
An element with atomic number 17 has this chemical symbol, name, and charge?
Cl or Chlorina
How many protons, neutrons, and electrons are in a "-1" Carbon-13 atom? Carbon has an atomic number of 6.
Note:
Electrons are always negative
Mass# = p + n
Charge = p + e
6 protons, 7 neutrons, and 7 electrons
After repeated experiments, scientists determine that the volume of a gas increases as its temperature increases, as long as pressure remains constant. This statement summarizes a consistent relationship but does not explain why it occurs. Is it a law, theory, or hypothesis?
Scientific Law
How many significant figures are in the measurement 0.04050?
Rust forming on an iron nail is this type of change
chemical change
Elements in Group 18A (rightmost column) are commonly known by this family name.
-halogens
-noble gases
-alkali metals
-alkali earth metals
noble gases
An ion contains 13 protons and 10 electrons. What is its charge and ion symbol?
Note: ion symbol just means the element has a charge
3+ charge and Al 3+
Scientists explain the behavior of gases by proposing that gas particles are constantly moving, are far apart, and collide with the walls of their container. This explanation accounts for several experimental observations. Is it a law, theory, or hypothesis?
Scientific Theory
Convert 3.25×10^5 micrograms into grams.
Note: Micro = 10^-6
0.325 grams
A reaction begins with 12.0 grams of one reactant and 5.5 grams of another. If 9.0 grams of solid product forms, what mass of gas must also have formed?
Note: Sum of Reactants = Sum of Products
8.5 grams
Which element is a metalloid (semi-metal): sodium, silicon, argon, or calcium?
Na, Si, Ar, Ca
Silicon
Write the isotope symbol for an atom containing 20 protons and 22 neutrons.
Note: isotope symbol is in the format element-mass#
Calcium-42
A student predicts that increasing the concentration of hydrochloric acid will increase the reaction rate because more acid particles will collide with magnesium each second. This prediction can be tested experimentally. Is it a law, theory, or hypothesis?
Note: this is a prediction based solely on his knowledge.
Hypothesis
A sample has a mass of 72.4 grams and a volume of 8.00 milliliters. What is its density?
9.05 g/mL
Propane Burning is an example of Endothermic or Exothermic Process?
Exothermic Process
Which family does the element Strontium (Sr) belong to?
- halogen
- noble gases
- alkali metals
- alkali earth metals
Alkaline earth metals
An element has two isotopes: 75% has a mass of 35 amu and 25% has a mass of 37 amu. What is the element’s average atomic mass?
35.5 amu
A 12.5-gram sample of one substance reacts with 7.5 grams of another substance in a closed container. What is the total mass of the products?
20.0 grams
Calculate and report the answer using the correct significant-figure rules:
(4.50+0.275)×2.0
Note: Calculate FIRST, then restart to find sig figs
9.6
Convert 68°F to Kelvin.
Note: F = 1.8C + 32
please memorize (1.8, 32) - Literally 2 Numbers :>
293 K
An element is located in Period 3 and Group 2A. Identify the element, its family, and the charge.
Note: Period means horizontal row
Magnesium, Mg 2+, alkaline earth metals
An ion is represented by the isotope symbol Fe-56, 3+. How many protons, neutrons, and electrons does it contain, and is it a cation or an anion?
26 protons, 30 neutrons, 23 electrons, and a cation