Answer:
Explanation:
Heat can transfer between objects in two different ways. Generally, heat will travel from places of higher heat to places of lower heat.
The first is conduction. This is when the object being heated and releasing heat are in direct contact. Not as much heat is lost in this process, since the thermal energy has nowhere else to go except for the object it is touching. An example would be putting a kettle on a hot stove, but it could also be grabbing a cold pole with your relatively warm hands.
The second is convection. This is where heat is radiated into the air, and thus, transferred by the air, to another object. The actual heat that you feel is actually electromagnetic waves, and its transfer from an object is called electromagnetic radiation. Convection is the heat you feel from a near fire or a space heater. This is also why wind is present in our atmosphere.
There is also radiation. This is caused from the burning or breaking down of a substance. This might come from the sun.
I hope I did enough to deserve the 45 points!
Answer: 
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
General representation of an element is given as: 
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
General representation of alpha decay :
The balanced nuclear equation when the isotope Strontium-90 decays by Q- decay is :
4) would be your correct answer
____NaNO3 + ___PbO --> ___Pb(NO3)2 + ___Na[2]O
To balace the eqaution, you need to have the same number of atoms for each element on both the reactant (left) and product (right) side.
To start off, you wanna know the number of atoms in each element on both sides, so take it apart:
[reactants] [product]
Na- 1 Na- 2
N- 1 N- 2(it's 2 because the the subscript [2] is outside of the parenthesis)
O- 4 O- 7 (same reason as above)
Pb- 1 Pb- 1
Na is not balanced out, so add a coefficient to make it the same on both sides.In this case, multiply by 2:
2NaNO3
Now Na is balanced, but the N and O are also effected by this, so they also have to be multiplied by 2 and they become:
Na- 2 Na- 2
N- 2 N- 2 (it balanced out)
O- 7 (coefficient times subscript, plus lone O) O- 7 (balanced out)
Pb was already balanced so no need to mess with it, just put a 1 where needed (it doesn't change anything).
Now to put it back together, it will look like this:
2NaNO3 + 1PbO --> 1Pb(NO3)2 + 1Na[2]O
Answer:
Ground state
the state with the smallest amount of energy.
