01:160:161 Lecture Notes - Lecture 9: Molar Mass, Atomic Number

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30 Dec 2019

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Chapter 3,4, & 6: matter, atoms, elements, & moles. Classifying matter according to its site and composition. If matter cannot be broken does into different types, it is considered a substance. Can be broken down into a simpler substance. Cannot be separated because its in its simplest form. If matter can be separated into different types, it is considered a mixture. A : mass number or the amount of protons plus the amount of neutrons in an element. Z : number of protons or the atomic number of the element. When an element has a different number of neutrons than the one on the periodic table. From atoms to ions (gaining and losing electrons) When the number of electrons is different that the protons, no longer making the element. The mole is a bridge that connects the microscopic world of atoms to our microscopic world where we measure mass and volume.

Related Questions

Indicate whether the following samples of matter is a heterogeneous mixture, a homogeneous mixture, a compound, or an element.

a. a blue-colored, single-phase liquid that when boiled away (evaporated) leaves behind a solid residue

b. a "cloudy" liquid that separates into two layers upon standing overnight

c. a non-uniform, white crystalline substance, part of which dissolved in alcohol and part of which does not dissolve in alcohol

d. a colorless gas that cannot be separated into simpler substances using physical means and that reacts with metal magnesium to produce both magnesium-oxygen compound and a magnesium-nitrogen compound

ceruleanclam950

I need help doing my lab homework, I missed lab that day because, I was sick and it's due.

Chemical Reactions and Equations Learning objectives To observe physical and chemical properties associated with chemical changes To be able to give evidence for the occurrence of a chemical reaction To write a balanced chemical equation To identify areaction as a combination, decomposition, precipitation, single or double replacement, or combustion reaction ntroduction When a substance undergoes a physical change, it changes its appearance but not its composition. For example, when ice melts to form water, it undergoes a physical change from solid to liquid. In a chemical change, the composition of a substance is changed to give a new substance with different physical and chemical properties. For example, when silver tarnishes, the shiny silver (Ag) changes to a dull gray silver sulfide (AgaS). Not only has the chemical formula changed from Ag to Agus, but also the physical properties (shininess) of the substance have changed. Some examples of physical and chemical changes are listed in Table 1 below. Table 1. Comparison of Physical and Chemical Changes Examples of Physical changes Examples and Evidence of Chemical Changes Change in state (melting, freezing, evaporating Formation of a gas (bubbles) subliming) Formation of a solid (precipitate) Change in size Tearing Change in Color Heat is given off or absorbed A solid dissolving in a solvent In a chemical reaction, atoms in the reactants are rearranged to produce new combinations of atoms in the products. However, the total number of atoms of each element in the reactants is equal to the total number of atoms in the products. This is true according to the Law of Conservation of Mass, which states that the total mass remains constant during a chemical reaction. In other words, matter cannot be created or destroyed in a chemical reaction. In a chemical equation, the reactants are shown on the left and the products are on the right. An arrow in between indicates that a chemical reaction occurs. Finally, the physical state of each compound is designated in parentheses after the chemical formula. Solid, liquid, gas, and aqueous (dissolved in water) are shown as(s,(n,(g), and (aq), respectively.

1) Classify each of the following as a mixture, a compound, or an element?

table sugar, propane, bronze, tea, vinegar, dry ice, oxygen, aluminum

2) Select the statements that pertain to elements. Select all the statements that apply.
a) These can be broken down by physical means.
b) These cannot be broken down by chemical means.
c) These combine chemically to form new substances; they are building blocks of matter.
d) These are chemical combinations of simpler forms of matter.
e) These are pure substances.

3) Which of the following are chemical changes? Check all that apply.
a) sugar is dissolved in water
b) a warm coke bottle fizzes when opened
c) the copper roof turns green over time
d) baking soda is dissolved in vinegar and bubbles appear
e) a fog appears on your windshield in cold weather

4) Classify each property as physical or chemical.

a)susceptibility to rust

b) flammability

c) boiling point

d) melting point

e) conductivity

f) color

5) Which of these substances are elements? Check all that apply.

a) silicon

b) iodine

c) lead

d) quartz

e) silicone

f) water

01:160:161 Lecture Notes - Lecture 9: Molar Mass, Atomic Number

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