Here are the answers in order:
1. During a physical change the substance changes physically.
2. The law of conservation of mass is a law stating the conservation of mass cannot be higher than 46mg or lower than 32mg.
3. A hypothesis is a guess that you make before completing a science experiment, it can be considered a law because it is important to know why you are making the guess.
4. During a chemical change the mass is changing colors. This is a representation of a chemical change.
5. Oil is a non-renewable resource, so it cannot demonstrate the conservation of mass.
6. When the color of the substance has changed or when it explodes.
7. Reactants are the objects that react when in a chemical change.
8. If you follow the rule of not going higher than 46mg and not lower than 32mg then it will automatically follow this law.
Chemical Reactions Part One Video:
1. mass
2. erupt-ant
3. reactant
4. object
5. mixtures
6. molecules
7. color changed
Questions again:
1. A chemical reaction
2. A physical change
3. Because if it is no higher than 46mg and no lower than 32mg then it will follow on it's own.
Whenever the fuel is being used up, a star explodes and the energy leakage from a star's core ceases.
Explanation:
The dying star expands in the "Red Giant," before even the inevitable collapse starts, due to nuclear reactions just outside of the core.
It becomes a white dwarf star when the star has almost the same density as the Sun. If it's much larger, a supernova explosion could take place and leave a neutron star away. However, if it is very large–at least three times the Sun's mass–the crumbling core of the star, nothing will ever stop it from crumbling. The star is imploding into a black hole, an endless gravitational loop in space.
You have to do a report :

So
the truck efficiency is 38%.
If the glasses and glove were wrong then I would chose the fire extinguisher and the power source should be the correct answer.
That's just what I would do though.
Answer:
K3PO4
Explanation:
Recall that colligative properties depends on the number of particles present. The greater the number of particles present, the greater the degree of colligative properties of the solution. Let us look at each option individually;
SrCr2O7-------> Sr^2+ + Cr2O7^2- ( 2 particles)
C4H11N (not ionic in nature hence it can not dissociate into ions)
K3PO4-------> 3K^+ + PO4^3- (4 particles)
Rb2CO3-------> 2Rb^+ + CO3^2- (3 particles)
Hence K3PO4 has the greatest number of particles and will display the greatest colligative effect.