FREE NYSTCE Chemistry Questions and Answers
In theory, as an ideal gas cools in a closed container, the pressure inside gradually decreases until it approaches that of a vacuum. What temperature should this happen at?
At 0 Kelvin (-273.15°C), an ideal gas in a closed container cools to a vacuum.
Which of the following accurately describes the rate of this chemical reaction?
Which statement best describes the density of the nucleus of an atom?
The nucleus has most of the atom's mass but little volume. Atoms have a tightly packed nucleus of protons and neutrons. Protons are positive and neutrons are neutral, but they make up almost all of the atom's mass.
Which action will cause the above response to shift to the right?
How many moles of carbon-12 are there in 6 grams of carbon-12?
"The molar mass of carbon-12 is needed to calculate the number of moles of carbon-12 in 6 grams
Carbon-12's molar mass is 12 grams:
We can calculate moles using the formula:
Number of moles = Mass (grams) / Molar mass
Moles = 6 grams/12 grams per mole
Moles = 0.5"
What is the equivalent in degrees Celsius of 423 kelvin?
"The conversion formula from Kelvin to Celsius is:
°C = K − 273.15
Consequently, in order to convert 423 Kelvin to Celsius, we would do the following:
°C = 423 − 273.15 = 149.85"
When a cold tire is inflated to a specific pressure and then heated by road friction, the pressure increases.
This occurs because of
When a cold tire is inflated to a certain pressure and then warms up due to friction with the road, the tire's pressure rises. This occurs because the air molecules inside the tire gain kinetic energy, causing them to move faster and collide with the tire's walls more frequently.
Which of these atoms has the greatest atomic radius?
Atomic radius is the distance between the center of the nucleus and the outermost electron shell. In general, as one descends a group (vertical column) in the periodic table, the atomic radius grows. The atomic radius increases as you move from right to left across a period (horizontal row) in the periodic table.
Which of the following elements shares silicon's Lewis dot structure?
In general, how do atomic masses vary across the periodic table of elements?
Atomic mass includes protons, neutrons, and electrons.
The periodic table arranges elements by increasing atomic number, which is the number of protons in an atom's nucleus. From left to right in the periodic table, atomic number and nucleus protons increase. Thus, atomic mass increases from left to right.
Why is cobalt (Co) listed before nickel (Ni) on the periodic table of elements, despite having a higher average atomic mass?
The periodic table lists elements by atomic number. Atomic number the number of protons in an atom's nucleus identifies the element. High-atomic-number elements have more protons. Cobalt (Co) precedes nickel (Ni) on the periodic table due to its lower atomic number. Cobalt has fewer nuclei protons than nickel.
The above model of ideal gases is useful because:
"Which of the following procedures will decrease the rate of reaction if the reaction below occurs in a sealed reaction chamber?
2CO + O2 ---> 2CO2"
Increasing the volume within the reaction chamber will reduce the rate of the reaction because it decreases the concentrations of the reactants and products as gases expand to fill the larger volume, which in turn affects the rate of the reaction.
Hydrogen peroxide naturally degrades over time into H2O and O2. MnO2 (manganese dioxide) can be used to decrease the activation energy required for this reaction, thereby accelerating its rate.
What kind of material is MnO2?
nO2 acts as a catalyst in this reaction, lowering the activation energy and increasing the reaction rate, thereby facilitating the decomposition of hydrogen peroxide.
For a hypothesis to reach the level of a theory it must be.
A hypothesis is a statement or prediction that can be tested and proposes an explanation for an observation or phenomenon. To become a theory, an idea is subjected to rigorous testing via experimentation and observation. Results are analyzed and evaluated by the scientific community. A well-supported explanation, supported by experimentation and observation, is widely accepted and consists of a comprehensive framework that explains and predicts associated phenomena.
Which substance is composed of numerous monomers joined in long chains?
Proteins are biomolecules composed of many amino acid monomers joined in long chains by peptide bonds, which gives them their unique structure and enables them to carry out a variety of essential functions in living organisms.