Answer:
element
Explanation:
we know that helium is a pure substance although helium atoms are sometimes mixed with their isotopes it is still the same element. since there is no other element combined with helium this makes it an element.
Boyle's law gives the relationship between pressure and volume of gas.
for a fixed amount of gas, at constant temperature the pressure of gas is inversely proportional to its volume.
PV = k
where P - pressure, V - volume and k - constant
P1V1 = P2V2
where parameters for the first instance are on the left side and parameters for the second instance are on the right side.
substituting the values in the equation
1.2 atm x 1.0 L = P x 4.0 L
P = 0.3 atm
new pressure is 0.3 atm
Answer:C11 -----^boron+positron
Explanation:the above reaction is nuclear reaction.
Positron emission causes the decrease in atomic number by one.
As in above example carbon-11is converted into boron isotop which has atomic number of 5.
After heating the brick and the iron, it is observed that the brick heats up quicker and the brick releases energy quicker.
<h3>What is thermal energy?</h3>
Thermal energy (also called heat energy) is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.
The iron has more energy than the brick even though it is at the same temperature. That means that the iron must have more particles than the brick.
Iron and brick are both solids and have the same volume, so the difference in total energy must be due to atomic composition.
Learn more about thermal energy here:
brainly.com/question/14506133
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