Unit test 1 Flashcards
Formula of Zinc Chloride
ZnCl2
Alloy definition
A solid that is a mixture of 2 or more ELEMENTS.
Is an alloy heterogenous or homogenous?
Homogenous
Because alloys appear to be uniform. Chemical composition is pretty even throughout.
What part of the Gold Foil experiment did we make an alloy of copper and zinc?
When we placed the penny with the zinc coating directly on the hot plate. When it turned gold.
Name of alloy that you produced between copper and zinc?
Brass
Did the mass of the penny increase or decrease after it turns silver?
Increase- because a zinc coating was added to the penny
Would the Mass of silver penny increase or decrease when it turned gold?
The mass would stay the same because we aren’t taking any atoms away.
(Adding more atoms=more mass)
True or False: “The copper atoms in the original penny turn into gold atoms by the end of the experiment”
The copper atoms mixed with the zinc atoms
Why is steel preferred over just using pure elemental iron?
- Doesn’t rust as easily
- More flexible
- Lighter
- Stronger (less brittle)
What did Ernest Rutherford discover?
He discovered that alpha particles passed through (mostly empty space)
How do u calculate density?
Mass divided by volune
What’s the density of water?
1.0 g/cm3
A
X
Z
What does each letter mean?
A=number of protons and neutrons
Z=number of the protons
X=element
Definition: ion
When the atom has a charge (can be positive or negative). This is determined by the number of electrons.
What’s an isotope?
When there is an imbalance of protons and neutrons. Determined by the number of neutrons.
What’s the mass number?
The number of protons and neutrons.
What’s atomic mass?
The total mass of particles of matter in an atom
What’s an alkali metal?
Any of the six chemical elements that make up Group 1 of the periodic table. They have one valence electron. Very reactive and are soft, shiny metals.
Noble gases
Is not that reactive. They have 8 valence electrons. Group 18
Nonmetal:
Not a metal. Form anions. Brittle and low melting point and are poor conductors
A period:
Is a row of chemical elements (ACROSS)
Combustion:
The process of burning something
Atomic number:
Number of protons
Octet rule
All elements try to combine with other elements by sharing or transferring electrons to fill their outer energy levels
Parts of an atom
Electrons protons and neutrons
Transition metals:
Elements that have valence electrons in two shells instead of only one. Great conductors of heat as well as electricity. Very malleable
Alkali Earth metals:
Have two valence electrons. Highly reactive and NOT naturally found in their elemental state. Group 2.
Law of conservation of matter:
Matter is neither created nor destroyed.
Cation
Positively charged ion
Element:
A SUBSTANCE that cannot be broken down into simpler substances
Compound
Made of two or more elements that were mixed CHEMICALLY
Mixture
Substances formed by PHYSICALLY mixing two or more substances
What is the gold foil experiment
Conducted by Ernest Rutherford. He used a thin lead tube to shoot positively charged particles (alpha particles) at a very thin sheet of gold foil.
Metal:
Has high conductivity. Malleable. High reflectivity of light
Anion
ION with a negative charge. More electrons
Groups/families:
Groups of elements with similar properties.
Ex: alkali metals, transition metals, halogens
Halogens:
A chemical element that forms a salt when reacting with a metal. 7 valence electrons.
How to calculate (weighted) average atomic mass?
(% abundance/100)(mass of isotope #1) + (% abundance/100)(mass of isotope #2)
What is a result of burning the candle?
H20, co2 and energy
What is needed to brun the candle
Fuel(candle wax) and oxygen and a spark from the match?
What we’re the chemical changes in the candle lab?
- When u blow into the line solution and mix it because you are utilizing a chemical and mixing it with something else
- Wax burning
What we’re some physical changes in the candle lab?
When the wax MELTS because it’s transitioning from solid to gas without using chemicals
What does AMU stand for
Atomic mass unit
What’s the difference between atomic mass and mass number
Mass number is the total number of protons and neutrons in one particular isotope. Atomic mass is the WEIGHTED average of all isotopes of that element that are naturally found on earth.
