Module 03 Online HW Review Bonus - CHEMISTRY
Elements A and Q form two compounds, AQ and A2Q3. The mass ratio (mass Q)/(mass A) for AQ is 0.574. What is the mass ratio (mass Q)/(mass A) for A2Q3?
0.861
A sample of pure lithium carbonate contains 18.8% lithium by mass. What is the % lithium by mass in a sample of pure lithium carbonate that has twice the mass of the first sample?
18.8 %
A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of definite proportion would predict that a 67 gram sample of chemical X should contain how many grams of carbon?
19 g
What is the atomic number of calcium?
20
Ethylene glycol has a molecular formula of C2H4(OH)2. How many hydrogen atoms are there in one molecule of the substance?
6
Methane and oxygen react to form carbon dioxide and water. What mass of water is formed if 3.2 g of methane reacts with 12.8 g of oxygen to produce 8.8 g of carbon dioxide?
7.2 g
Which one of the following is the best electrical conductor?
Al
The symbol for bromine is:
Br
The scientist who discovered the law of conservation of mass and is also called the father of modern chemistry is:
Lavoisier
Heptane is always composed of 84% carbon and 16% hydrogen by mass. What law does the observation illustrate?
Law of Definite Proportions
Write the formula for a compound consisting of 3 sodium atoms, 1 phosphorus atom, and 4 oxygen atoms:
Na3PO4
Which gas is monatomic at STP?
Neon
A student heats 0.5585 g of iron with 0.3350 g of sulfur. She reports that she obtains 0.8792 g of iron sulfide and recovers 0.0433 g of unreacted sulfur. Show by calculation whether or not her results obey the law of conversation of mass.
No, because the sum of the initial masses is less than the sum of the final masses. No, because there is no iron left over. Yes, because the percentage of iron is definitely 63.52% in the compound. No, because the number of grams of iron(II) sulfide is less than the grams of iron and sulfur that she started with. Yes, because the sum of initial masses is more than the sum of the final masses.
Magnesium metal melts at 650 oC.
This is a physical property.
An element is a substance that:
cannot be decomposed into two or more pure substances.
A chemical mixture is distinguished from a chemical compound in that:
chemical compounds may be found in a chemical mixture.
The opposite of vaporization is called:
condensation
Which of the following is a trace mineral in the body?
copper
The freezing point of a substance is ________ the melting point of the substance.
equal to
Which of the following techniques would be most effective in separating the components of salt water?
evaporation
For most substances, the distance between the particles is smallest when the substance:
exists as a crystalline solid.
A banana split is an example of a(n):
heterogeneous mixture
Which state of matter retains its volume but adapts its shape to that of its container is:
liquid
Glycerol changes its shape to conform to its container and has a fairly high density. Glycerol is a:
liquid.
Substances required in large amounts by the body are called:
macronutrients
Which of the following is a homogeneous mixture?
more than one of the choices whole wheat bread sugar water water salt
Small compressibility is a characteristic of which state of matter?
more than one response is correct (Liquid, solid, gas)
The Law of Conservation of Energy states which of the following?
one of these Kinetic energy is conserved. Energy cannot be converted from one form to another. Potential energy is conserved.
The measure of the average kinetic energy of the particles of a substance is the:
temperature
Which of the following is true of ice, water and steam?
they are the same substance in different physical states
