Chemical Reactions
How does a chemical reaction change differs from a physical change?
In a chemical reaction a new substance is formed and in a physical change, no new substance is formed.
A car travels 60 m in 12 s. What is its velocity? v=d/t
60m/12s= 5m/s
What is the unit for energy?
Joules (J)
What type of energy is stored in a stretched rubber band?
Elastic Potential Energy
What theory explains how the universe began from a single point and has been expanding ever since?
The Big Bang Theory
What law does the equation CH₄ + 2O₂ → CO₂ + 2H₂O demonstrate?
Law of Conservation of Mass – atoms are neither created nor destroyed.
A car speeds up from 10 m/s to 20 m/s in 5 s. What is the acceleration? a = Δv ÷ t
A ball is held at the edge of a building. Is this an example of kinetic or potential energy?
Potential energy
What type of energy is found in food and batteries?
chemical Energy
If V = 12V and R = 4Ω, what is I? V=IR
3 A =I (Current)
In the equation CH₄ + 2O₂ → CO₂ + 2H₂O, how many of each atom are on the reactant side?
1 Carbon, 4 Hydrogen, 4 Oxygen
A 20 kg object accelerates at 3 m/s². What is the net force? F = m × a
20m/s/s × 3kg = 60 N
W = F × d
A student pushes a box with 20 N for 3 meters. How much work is done?
W = F × d = 20N × 3m = 60 J
What color of light wave has the longest wavelength?
Red
What does redshift show us?
Galaxies are moving away; universe is expanding
__ C₃H₈ + __ O₂ → __ CO₂ + __ H₂O
1 C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O (1,5,3,4)
A box is pushed right with 30 N and friction is 10 N left. What is net force & direction?
Net Force = 30N − 10N = 20 N right
A 5 kg ball is 2 m high. What is GPE? GPE = mgh
5kg × 9.8m/s/s × 2m = 98 J
Which form of energy is released from the splitting or fusion of atomic nuclei?
Nuclear Energy
Define voltage and current.
Voltage = energy per charge,
Current = flow of electrons
C₃H₈ + 5O₂ → ? (Find the correct balanced product side)
3CO₂ + 4H₂O
A 50 kg sled is pulled with 100 N. What is the acceleration? F=ma
a = F ÷ m = 100 ÷ 50 = 2 m/s²
A baseball with a mass of 0.15 kg is pitched at a speed of 40 m/s.
What is the kinetic energy of the baseball? KE=(1/2)mv2
120 J = KE
A wave has a frequency of 5 Hz and a wavelength of 2 meters.
What is the speed of the wave? (V=f×wavelength)
Final Jeopardy: Wave
Speed=5Hz×2m=10m/s
What are the three main types of galaxies in the universe?
spiral, elliptical, and irregular