1.
Chemical Equation: Zn(s)+ CuSO4(aq) → Cu(s) + ZnSO4(aq)Mass of empty beaker: 0.97gMass of beaker + zinc before reacting: 1.17gVolume of copper(II) sulfate before reacting: 45.2 mLMass of dry filter paper before filtering: 0.66gMass of filter paper + brown chunks after drying over night: .85gHow many grams of zinc did the student use in this experiment?How many grams of brown chunks of residue did experiment product?What are those brown chunks made of?What is the mass ratio of copper to zinc in this reaction?
2.
Select one of the following that are pHYSICAL changes:
Correct Answer
B. Squishing a lemon to make lemonade
Explanation
Squishing a lemon to make lemonade is a physical change because it involves a change in the physical state or appearance of the lemon. The lemon is being physically crushed or squished, but its chemical composition remains the same. The lemonade is made by extracting the juice from the lemon, which is a physical process. Therefore, this is a physical change.
3.
A science teacher shows students a chunk of gold and a very thin sheet of gold.How would a picture of one atom from the chunk of gold compare to a picture of one atom from the thin sheet of gold?
Correct Answer
C. The atoms in the chunk and the thin sheet would be the same.
Explanation
The correct answer is that the atoms in the chunk of gold and the thin sheet of gold would be the same. This means that regardless of whether the gold is in chunk form or in a thin sheet, the individual atoms that make up the gold will be identical.
4.
Hydrogen, carbon and oxygen are added together in a closed container.After they are mixed, a chemical reaction takes place and a liquid is formed.How does the number of atoms after the reaction compare to the number of atoms before the reaction?
Correct Answer
C. The total number of atoms remains the same
Explanation
In a chemical reaction, atoms are rearranged to form new substances, but the total number of atoms remains constant. This is known as the law of conservation of mass. Therefore, the total number of atoms after the reaction will be the same as the total number of atoms before the reaction.
5.
In one of our experiments, we tested several elements using different properties to see if we could find elements that could be grouped together if they share some properties. - One of those properties that we tested was the ability to react with oxygen to make an "oxide" . Which of the following is true about this property?
Correct Answer
C. It is a chemical property because when you can test it the element changed into something else.
Explanation
The ability of an element to react with oxygen and form an oxide is a chemical property because it involves a chemical change. When an element reacts with oxygen, it undergoes a chemical reaction and transforms into a different substance, which is the oxide. This is different from a physical property, which can be observed or measured without changing the identity of the substance. Therefore, the correct answer is that it is a chemical property because when you test it, the element changes into something else.
6.
Select ALL of the following that are pHYSICAL changes:
Correct Answer(s)
C. Crumpling up an old quiz
D. A basketball deflating
E. Breaking a piñata
Explanation
The given answer options are all examples of physical changes. A physical change is a change in the physical properties of a substance, where the substance remains the same chemically. In the case of a basketball deflating, the physical property of the basketball (its volume) is changing. Crumpling up an old quiz also changes the physical appearance of the paper, but it is still paper. Breaking a piñata involves physically breaking the object, but it remains the same material. Therefore, all three options are examples of physical changes.
7.
Your teacher is up front showing you an orange object that she says will melt at 39oC that quickly turns whitewhile sitting in the air. The object is very malleable and bends in her hands. - Which of the properties are chemical properties?
Correct Answer
B. The object turns white in the air
Explanation
The object turning white in the air is a chemical property. Chemical properties describe how a substance reacts with other substances to form new substances. In this case, the orange object undergoes a chemical reaction with the air, causing it to change color and turn white. This indicates that there is a chemical change happening in the object.
8.
Assume that you have the technology to cut a piece of gold into the smallest piece possible. What would you be left with?
Correct Answer
C. A single atom of gold that is too small to be seen
Explanation
When a piece of gold is cut into the smallest piece possible, it would be left with a single atom of gold that is too small to be seen. Atoms are the basic building blocks of matter, and they cannot be divided further without losing their identity. Since gold is made up of atoms, cutting it into the smallest piece would result in a single atom. This atom would be too small to be seen with the naked eye due to its microscopic size.
9.
Who discovered energy levels?
Correct Answer
D. Bohr
Explanation
Bohr is the correct answer because he proposed the concept of energy levels in atoms. In 1913, Niels Bohr introduced his atomic model, which stated that electrons orbit the nucleus in specific energy levels or shells. These energy levels are quantized, meaning that electrons can only exist in certain discrete energy states. This model successfully explained the stability of atoms and the emission and absorption of light. Bohr's discovery of energy levels revolutionized our understanding of atomic structure and laid the foundation for modern quantum mechanics.
10.
A very thin piece of iron is placed in the path of a beam of alpha particles. What do you expect will happen?
Correct Answer
C. Most of the particles will pass right through iron
Explanation
Alpha particles are large and heavy compared to other types of particles, such as electrons. They have a positive charge and high energy. When alpha particles pass through a very thin piece of iron, most of them will pass right through because the iron atoms are mostly empty space. The positive charge of the alpha particles is not strong enough to interact significantly with the iron atoms. Therefore, the majority of the alpha particles will not be deflected or stopped by the iron and will continue on their path.
11.
Compared to the charge and mass of a proton, an electron:
Correct Answer
B. Has the opposite charge and much less mass
Explanation
Electrons are negatively charged and very light compared to protons
12.
What did Niels Bohr say about the electrons in the atom?
Correct Answer
C. Electrons are in rings called "orbits", that circle the center of the atom
Explanation
Protons are in the center of the atom
13.
In the Cathode-Ray experiment, what name did Thomson give the particles that made up the beam?
Correct Answer
A. Electrons
Explanation
The beam is negatively charged so it's made up of electrons
14.
What did Ernest Rutherford help to discover?
Correct Answer
E. Nucleus
Explanation
Ernest Rutherford helped to discover the nucleus. He conducted the famous gold foil experiment in which he bombarded a thin gold foil with alpha particles. Through this experiment, he observed that most of the alpha particles passed straight through the foil, but a few were deflected at large angles. Rutherford concluded that the deflections were due to a small, dense, and positively charged region at the center of the atom, which he called the nucleus. This discovery revolutionized the understanding of atomic structure and paved the way for further advancements in nuclear physics.
15.
Determine the molar mass (formula mass) for B2(Cr2O7)3
Correct Answer
669.577 g/mol
Explanation
The molar mass (formula mass) for B2(Cr2O7)3 is 669.577 g/mol. This value represents the sum of the atomic masses of all the atoms in one mole of the compound. The compound contains 2 boron atoms, 2 chromium atoms, and 21 oxygen atoms. By multiplying the atomic masses of each element by their respective number of atoms and summing them up, we can calculate the molar mass of the compound.
16.
A ______ is a group of two or more atoms held together by chemical bonds.
Correct Answer
molecule, Molecule, molecules, Molecules
Explanation
Molecules are the fundamental building blocks of many substances. They can be composed of atoms of the same element, such as oxygen (O2), or different elements, such as water (H2O). The chemical bonds that hold atoms together in a molecule determine its properties and how it interacts with other substances.
17.
Determine the molar mass (formula mass) for Ca(C2H3O2)2
Correct Answer
158.1654 g/mol
Explanation
The molar mass (formula mass) for Ca(C2H3O2)2 is 158.1654 g/mol. This value is obtained by adding up the atomic masses of all the atoms in the formula unit. In this case, we have one calcium atom (Ca) with a molar mass of 40.08 g/mol, two acetate ions (C2H3O2) with a molar mass of 59.04 g/mol each. Adding these masses together gives us a total molar mass of 158.1654 g/mol.
18.
Who's atom model is this?
Correct Answer
C. Thomson
Explanation
The correct answer is Thomson because his atomic model, also known as the "plum pudding" model, proposed that atoms are composed of positively charged particles with negatively charged electrons embedded within them. This model was based on the discovery of electrons and their properties, and it was a significant contribution to the understanding of atomic structure. Rutherford's model came after Thomson's and proposed the existence of a small, dense nucleus at the center of the atom, while Bohr's model incorporated the concept of energy levels and orbits for electrons. Dalton's atomic theory laid the foundation for modern atomic theory but did not provide a specific model of the atom.
19.
Who's atom model is this?
Correct Answer
B. Rutherford
Explanation
Rutherford's atom model is the correct answer because he proposed the nuclear model of the atom, also known as the planetary model. In this model, Rutherford suggested that the atom consists of a small, dense, positively charged nucleus at the center, with negatively charged electrons orbiting around it. This model was based on Rutherford's famous gold foil experiment, which showed that most of the atom's mass and positive charge is concentrated in the nucleus.
20.
Define Scientific Law
Correct Answer
A. Gives an explanation for your observations
Explanation
A scientific law is a statement that describes a natural phenomenon or behavior based on repeated observations and experiments. It provides an explanation for the observations made and helps to understand the underlying principles or rules governing the phenomenon. Scientific laws are derived from empirical evidence and are considered to be universally applicable. They serve as a foundation for scientific theories and can be used to predict future observations or outcomes.
21.
Define Scientific Theory
Correct Answer
B. Tells what has been observed
22.
Define Physical Property
Correct Answer
A. Measuring a property that does not change the chemical composition.
Explanation
Examples of Physical: conductivity, magnetic, basic or acidic, luster, malleable, ductile
Examples of Chemical: reacts with HCl, reacts with oxygen
23.
Define Chemical Property
Correct Answer
B. Something undergoes a change in composition, a new substance is formed.
Explanation
Examples of Physical: conductivity, magnetic, basic or acidic, luster, malleable, ductile
Examples of Chemical: reacts with HCl, reacts with oxygen
24.
Which of the following have a mass of 1 amu?
Correct Answer(s)
A. Proton
C. Neutron
Explanation
The correct answer is Proton and Neutron. Protons and neutrons both have a mass of approximately 1 atomic mass unit (amu). Electrons, on the other hand, have a much smaller mass compared to protons and neutrons, and their mass is usually considered negligible in comparison. Therefore, only protons and neutrons have a mass of 1 amu.
25.
Which pair below are isotopes of each other?
Correct Answer
D. Carbon-12 and carbon-14
Explanation
Isotopes are atoms of the same element that have different numbers of neutrons. Carbon-12 and carbon-14 are isotopes of each other because they both have the same number of protons (6) but different numbers of neutrons. Carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons.
26.
A fictional element has only two naturally occurring isotopes. The isotope with mass number 25 makes up 30% of that element on earth, and the isotope with mass number 27 makes up 70% of that element on earth. Which of these is closest to the atomic mass of this element?
Correct Answer
A. 26.5
Explanation
The atomic mass of an element is the weighted average of the masses of all its isotopes, taking into account their relative abundance. In this case, the element has two isotopes, one with a mass number of 25 and the other with a mass number of 27. The isotope with mass number 25 makes up 30% of the element, while the isotope with mass number 27 makes up 70%. To find the atomic mass, we can calculate the weighted average using the formula: (30% x 25) + (70% x 27) = 26.5. Therefore, the closest atomic mass to this element is 26.5.
27.
Determine the number of each subatomic particle:
Correct Answer
A. Electrons = 5
Neutrons =6
Protons =5
Explanation
The number of electrons in an atom is equal to the number of protons, so if there are 5 protons, there must be 5 electrons. The number of neutrons can vary, but in this case, there are 6 neutrons. Therefore, the correct answer is Electrons = 5, Neutrons = 6, Protons = 5.
28.
How many valence electrons do atoms have in column 13 of the periodic table?
Correct Answer
3
Explanation
13th column 3 electrons
29.
Write the electron configuration for Lr?
Correct Answer
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 5f¹⁴ 6d¹⁰ 7s² 6f¹⁴ 7p¹ 7d¹ 8s² , [Rn] 7s² 5f¹⁴ 6d¹⁰ 7p¹ 7d¹ 8s²
Explanation
The given electron configuration represents the electron distribution in the element Lawrencium (Lr). The numbers and letters in the configuration represent the energy levels (1s, 2s, etc.) and the orbitals (s, p, d, f) within each energy level. The superscript numbers represent the number of electrons in each orbital. Therefore, the electron configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d1 indicates that Lawrencium has 103 electrons, with the last electron occupying the 6d orbital.
30.
Give 7 patterns that show themselves on the periodic table:
Correct Answer
To name a few:
element symbol, ammout of protons, seperated by block (S, D, P, F), they are seperated by isotope averages, # of valance electrons, famlies or element similarty, metals, non-metals, metaliods, atomic number, enegry level, Electronegativity
Explanation
The answer provides a list of patterns that can be observed on the periodic table. These patterns include the element symbol, the number of protons, the block they belong to (S, D, P, F), isotope averages, the number of valence electrons, families or element similarity, classification as metals, non-metals, or metalloids, atomic number, energy level, and electronegativity. These patterns help organize and categorize the elements on the periodic table based on their properties and characteristics.
31.
Where are protons located on the atom?
Correct Answer
B. The center
Explanation
Protons are located in the center of the atom, specifically in the nucleus. The nucleus is the small, dense region at the center of an atom where protons and neutrons are found. This is where most of the mass of the atom is concentrated. The electron cloud, on the other hand, surrounds the nucleus and contains the electrons, which are negatively charged particles. Therefore, the correct answer is "The center."