chemistry
Which of the following is a distinguishing characteristic of elements in Group 18, the noble gases?
They are largely unreactive and stable.
Which of the following is a chemical property of the element aluminum?
It forms a protective oxide layer.
What is the correct chemical formula for the compound ammonium sulfate?
(NH4)2SO4
Which of the following indicates a physical change rather than a chemical change?
Melting ice
In the neutralization reaction, nitric acid + potassium hydroxide → water + what other product?
potassium nitrate
What is the correct chemical name for the compound with the formula (NH4)3PO4?
ammonium phosphate
What is the name of the compound with the formula SO2?
sulfur dioxide
Elements in Group 17 are commonly known by what collective name?
Halogens
Compounds formed by covalent bonds typically have which of the following characteristics?
Low melting points
Which of these human activities is a primary contributor to the formation of acid rain?
Burning of fossil fuels
When an iron nail rusts and increases in mass, why does this phenomenon not violate the law of conservation of mass?
The nail is combining with atmospheric oxygen.
What is the general trend for atomic radius as you move down a group in the periodic table?
It generally increases.
According to the Arrhenius definition, what do acids produce when dissolved in water?
Hydrogen ions (H+)
What type of reaction typically involves one reactant breaking down into two or more simpler substances?
Decomposition reaction
Oxides of sulfur and nitrogen from power plants can lead to environmental damage in the form of what type of precipitation?
acid precipitation
What is the numerical pH value of a sample of pure water at 25 degrees Celsius?
7
Is the following chemical equation correctly balanced: CH4 + 3 O2 → CO2 + 4 H2O?
No, it is not balanced correctly.
What is the correct chemical name for the compound with the formula CCl4?
carbon tetrachloride
As the concentration of hydrogen ions [H+] in a solution increases, what happens to the pH value?
The pH value decreases.
What is the correct chemical name for the compound with the formula SnCl4?
tin(IV) chloride
Which of the following represents the balanced chemical equation for the decomposition of hydrogen peroxide?
2 H2O2 → 2 H2O + O2
What is the correct chemical formula for the compound iron(II) chloride?
FeCl2
The reaction 2 H2 + O2 → 2 H2O is an example of which type of reaction?
synthesis
When zinc (Zn) is added to sulfuric acid (H2SO4), a gas is produced. What is the identity of this gas?
Hydrogen gas
Which of the following chemical formulas represents a compound?
CO
Which of the following is a characteristic property of elements found in Group 2, the alkaline earth metals?
They readily form +2 ions.
Which of the following is a characteristic property of elements found in Group 1, the alkali metals?
They are highly reactive metals.
When neutralizing a base like ammonia cleaner with an acid, what is the primary safety precaution the janitor should take?
Wear appropriate personal protective equipment.
Why are hydrogen peroxide bottles typically made from dark brown glass or plastic?
To protect it from decomposition by light.
The reaction 2 AgNO3 + Cu → 2 Ag + Cu(NO3)2 is classified as which type of reaction?
single displacement
What is the correct chemical name for the compound with the formula CO?
carbon monoxide
What are the two main products formed in a typical acid-base neutralization reaction?
A salt and water
Which of the following correctly represents the balanced chemical equation for the reaction of hydrochloric acid and potassium hydroxide?
HCl + KOH → KCl + H2O
Which of the following is a physical property of the element aluminum?
Its relatively low density.
A solution with a pH of 2 would be classified as:
strongly acidic
Which of the following is the balanced chemical equation for the reaction of zinc with sulfuric acid?
Zn + H2SO4 → ZnSO4 + H2
How are covalent bonds primarily formed between atoms?
By sharing electrons between atoms
What is the name of the compound K2CO3?
potassium carbonate
What is the chemical formula for calcium hydroxide?
Ca(OH)2
According to the law of conservation of mass, in a chemical reaction:
The total mass of reactants equals the total mass of products.
How many electrons does a neutral atom of oxygen (atomic number 8) typically possess?
8
In which of the following pairs do the atoms or ions have the same total number of electrons?
F- and O2-
Which of the following is a major environmental consequence of acid precipitation?
Damage to aquatic ecosystems
Among tap water, whole milk, lemon juice, and drain cleaner, which liquid would be expected to have the highest concentration of hydrogen ions?
Lemon juice
What is the correct chemical name for the compound with the formula FeCl3?
iron(III) chloride
An unknown element X forms a compound with aluminum (Al) with the empirical formula Al2X3. What would be the most likely formula for a compound formed between element X and calcium (Ca)?
CaX
Among tap water, whole milk, lemon juice, and drain cleaner, which liquid would be expected to have the highest pH value?
Drain cleaner
What coefficient is needed for O2 to balance the equation: C3H8 + __ O2 → 3 CO2 + 4 H2O?
5
Which group of elements on the periodic table is known for having one valence electron and being very reactive?
Group 1
Which type of bond involves the electrostatic attraction between oppositely charged ions?
Ionic bond
What is the chemical formula for sodium chloride?
NaCl
An atom that has lost one or more electrons becomes what kind of particle?
A cation
A substance's boiling point is categorized as which type of property?
A physical property
Which indicator was suggested to the janitor for neutralizing ammonia with hydrochloric acid?
Phenolphthalein
What is the systematic name for the compound with the chemical formula H3PO4?
phosphoric acid
The chemical equation KCl + AgNO3 → KNO3 + AgCl represents which specific type of chemical reaction?
double displacement reaction
What is the correct chemical formula for the compound aluminum oxide?
Al2O3
What is generally true about the pH value of highly acidic solutions?
They typically exhibit a low pH value.
Which of the following properties of a substance is a chemical property?
flammability
What type of substance is ammonia cleaner (NH4OH) commonly classified as in chemistry?
A weak base
Which of the following is an example of a physical property of aluminum?
Its high electrical conductivity.
What is the correct chemical name for the compound (NH4)3PO4?
Ammonium phosphate.
Which of the following is considered a major greenhouse gas contributing to climate change?
Carbon dioxide (CO2).
What is the correct chemical name for the compound SnCl4?
Tin(IV) chloride.
If element X combines with aluminum to form Al2X3, what is the most likely formula for the compound formed between element X and calcium?
CaX.
Which of the following is an example of a chemical property of aluminum?
Its reactivity with strong bases.
Which characteristic best describes elements found in Group 2 of the periodic table?
Shiny, somewhat soft metals that are reactive.
An iron nail gains mass when it rusts. How does this observation relate to the law of conservation of mass?
The added mass comes from oxygen in the air reacting with the iron.
A solution with a pH of 13 would be classified as what?
Strongly basic.
Which of the following is a characteristic property of most metals?
Malleable and ductile.
What is the balanced chemical equation for the decomposition of hydrogen peroxide?
2H2O2 → 2H2O + O2.
In a chemical reaction, the gain of electrons by an atom or ion is referred to as what?
Reduction.
Which characteristic best describes elements found in Group 18 of the periodic table?
Very stable, unreactive gases.
A covalent bond in which electrons are shared unequally between two atoms is described as what?
Polar covalent.
Which characteristic best describes elements found in Group 1 of the periodic table?
Shiny, soft metals that are highly reactive.
Which indicator is commonly used to observe the endpoint of an acid-base neutralization reaction?
Phenolphthalein.
Which of the following chemical formulas represents a compound?
CO
The release of oxides of sulfur and nitrogen into the atmosphere is primarily responsible for which environmental phenomenon?
Acid precipitation.
According to the Arrhenius definition, an acid is a substance that produces which ion when dissolved in water?
Hydrogen ion (H+).
What is the primary role of a catalyst in a chemical reaction?
To decrease the activation energy of the reaction.
What is the name of the compound with the formula H3PO4?
phosphoric acid
Which of the following is the balanced chemical equation for the reaction of hydrochloric acid with potassium hydroxide?
HCl + KOH → KCl + H2O
What is the pH of pure water?
7
What constant represents the number of particles (atoms, molecules, ions) in one mole of a substance?
Avogadro's number.
What type of reaction occurs when ammonia cleaner (a base) is neutralized with hydrochloric acid?
Acid-base neutralization reaction.
What is the correct chemical formula for ammonium sulfate?
(NH4)2SO4.
What does the atomic number of an element represent?
The total number of protons in the nucleus.
What is the correct chemical name for the compound CO?
Carbon monoxide.
How is the mass number of an atom determined?
By summing the protons and neutrons.
What type of chemical reaction is represented by the equation KCl + AgNO3 → KNO3 + AgCl?
Double displacement reaction.
Which of the following properties of a substance is a chemical property?
flammability
What do elements in the same period of the periodic table have in common?
The same number of electron shells.
The equation for the reaction of silver nitrate and copper is 2 AgNO3 + Cu → 2 Ag + Cu(NO3)2. Which type of reaction is this?
single displacement
Consider the reaction: CH4 + O2 → CO2 + H2O. What are the correct coefficients for O2 and H2O, respectively, to balance this equation?
2 and 2
In which of the following pairs do the atoms or ions have the same total number of electrons?
F− and O2−
What is the correct chemical name for the compound FeCl3?
Iron(III) chloride.
An atom becomes a positively charged ion by doing what?
Losing an electron.
What type of chemical bond involves the transfer of electrons between atoms?
Ionic bond.
In chemistry, what term describes an ionic compound formed from the neutralization reaction of an acid and a base?
A salt.
A chemical reaction that absorbs energy from its surroundings is known as what?
Endothermic reaction.