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:
pH measures ratio of H+ ions to OH- ions of substances
pOH measures ratio of OH- ions to H+ ions of substances
Explanation:
pH is a scale which measures the ratio of H+ ions to OH- ions to identify how acidic or basic a substance is. This is because acidic substances have high amounts of H+ ions and low amounts of OH- ions, and therefore have a higher ratio of H+ to OH- ions. (And vice versa for bases, low H+ to OH- ratio) On a pH scale, acidic substances have a pH of 0 to 7, water (neutral pH, not acidic nor basic) has a pH of 7, and bases have a pH of 7-14.
pOH is very similar to pH but measures the opposite: the ratio of OH- ions (indicative of a base) to H+ ions (indicative of an acid). Therefore the pH values are reversed on the scale: Basic substances have pOHs below 7, and acidic substances are above 7 on the pOH scale.
Fundamentally, these two scales measure the same thing is the same way, one just measures the ratio one way (H+:OH-), while the other measured them the other way (OH-:H+), resulting in flipped values on the scales:
pH: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
<---Acidic---> <------Basic------->
pOH: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
<----Basic----> <-----Acidic------->
Hope this helped!
Answer:
A group of dissimilar elements with a net charge remaining is called a polyatomic ion.
Explanation:
Answer: A) Water Explanation: Water molecules are polar molecules
Answer:
97 J
Explanation:
Step 1: Given data
- Mass of the sample (m): 12 kg
- Specific heat capacity (c): 0.231 J/kg.°C (this can also be expressed as 0.231 J/kg.K)
- Initial temperature: 45 K
Step 2: Calculate the temperature change
ΔT = 80 K - 45 K = 35 K
Step 3: Calculate the heat required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.231 J/kg.K × 12 kg × 35 K = 97 J