The amount left after 20 years = 154.15 mg
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
The main particles are emitted by radioactive elements so that they generally decay are alpha (α), beta (β) and gamma (γ) particles
The decay formula for isotope :
Then for t=20 years, the amount left :
Answer:
447,25k
Explanation:
According to the ideal gas law
Where:
P: is the pressure of the gas in atmospheres.
V: is the volume of the gas in liters.
n: number of moles of the gas
R: ideal gas constant
T: absolute temperature of the gas in kelvin
now using:
Independent variable: the student chooses to miss class.
dependent variable: in result of the student missing class his grade goes down.
hyposthesis: if the student misses class multiple times, then his grades will go down.
A. The heat is needed to melt 100.0 grams of ice that is already at 0°C is +33,400 J.
<h3>What is Specific heat capacity?</h3>
Specific heat capacity is the quantity of heat needed to raise the temperature per unit mass.
<h3>
Heat needed to melt the cube of ice</h3>
The heat is needed to melt 100.0 grams of ice that is already at 0°C is calculated as follows;
Q = mL
where;
- m is mass of the ice
- L is latent heat of fusion of ice = 334 J/g
Q = 100 x 334
Q = 33,400 J
Thus, the heat is needed to melt 100.0 grams of ice that is already at 0°C is +33,400 J.
Learn more about heat capacity here: brainly.com/question/16559442
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D. The number increases and then decreases for noble gases
