SI Units + Temperature
What is the SI base unit for length?
This term refers to how close a measured value is to the true or accepted value.
What is Accuracy
Convert 3 feet to inches using dimensional analysis.
1 ft = 12in
what is
3 ft x 12in/1ft = 36 in
Physical change - chemical composition of substance not altered
Chemical change - Chemical changes change the chemical structure of a substance by breaking and/or forming chemical bonds
How many sig figs in 0.0000102?
What is the SI base unit for mass?
When a set of measurements are consistently close to each other, regardless of whether they are close to the true value, they are said to be this.
What is Precision.
Convert 10 grams to kilograms.
1kg = 1000g
10 g x 1kg/1000g = 0.01 kg
2) What is a compound?
1) Two or more pure substances physically combined
Ex. cereal + milk
2) A compound is a chemical combination of elements that has its own set of properties and a definite composition
Ex: NaCl, or Table Salt
what is 19.5
Write the equation for temperature in Kelvin?
what is
K = C + 273.15?
A set of measurements taken of the same object are: 5.1, 5.0, and 5.2 cm. The true value is 5.0 cm.
Is it accurate, precise, or both?
what is accurate and precise/ both.
Convert 5 mi/h to m/s
1 mi = 1.6094 km
1km = 1000m
1 hour = 60 min
1min = 60 sec
what is
5mi/1 hr x 1.6094km/1mi x 1000m/1km x 1 hr/60min x 1min/60 sec
= 2.24 m/s
what is the Law of conservation of energy?
Energy cannot be created or destroyed but can be converted from one another.
ex. potential energy --> kinetic energy
round to correct amount of sig figs.
what is 154.5
What is the boiling + freezing point of water in degree Kelvin AND degree Celsius?
Kelvin Freezing: 273.15 K
Kelvin Boiling: 373.15 K
Celsius Freezing: 0 C
Celsius Boiling: 100 C
In repeated trials, a student records measurements of the same object as: 10.5, 10.5, and 10.5 g, but the true mass is 10.0 g.
Is it precise, accurate, or both?
What is precise.
1) What is the mass of an object that has a volume of 11.2 ml and a density of 3.2 g/ml?
2) Also what is the density in kg/L?
1) d = m/v --> m=d x v
1) m= (3.2g/ml) x (11.2ml) --> m = 35.84 g
2) g/ml --> kg/L
2) 3.2g/1ml x 1kg/1000g x 1000ml/1L = 3.2kg/L!!
What is an intensive property?
Give examples.
1) Extensive: Properties that depend on amount of substance
1) example: mass changes with amount present.
2) Intensive: Properties that do not change regardless of amount of substance.
2) Example: a sliced strawberry and full strawberry are both red.
1.27 x 105
Your resting body temperature is 36 degrees Celsius.
In respect to SI base units, what is the temperature?
SI base unit for temp is Kelvin (K.)
K = C + 273.15
K = 36 + 273.15
K = 309.15
A student measures the length of an object three times and records the values: 14.3 cm, 15.7 cm, and 13.5 cm. The true length is 14.0 cm. What term best describes these measurements?
What is neither precise or accurate.
Convert 15 micrograms to kilograms.
1microgram = 1x10-6grams
1kilogram = 1x103grams
so...
15micrograms x 1x10-6grams/ microgram x 1kilogram/1x103grams =
Explain:
Hypothesis vs. Law vs. Theory.
Hypothesis:inital explanation of observed fact that is able to be tested and revised via experimentation.
Law: Scientific law that is always observed to be true.
Theory: explain + predict many observations liked by underlying phenomenon
(15.105 + 2.12) x (4.61256) = ?
round to correct amount of sig figs.
what is 79.451