This must be a universal indicator, the pH is going down everytime you add more :)
Radioactive material undergoes 1st order decay kinetics.
For 1st order decay, half life = 0.693/k
where k = rate constant
k = 0.693/half life = 0.693/8.02 = 0.0864 day-1
Now, for 1st order reaction,
k =

Given: t = 6.01d, initial conc. = 5mg
∴0.0864 =

∴ final conc. = 2.975 mg
Answer:
STP stands for Standard Temperature and Pressure. NTP stands for Normal Temperature and Pressure.
Explanation:
STP is set by the IUPAC as 0°C and 100 kPa or 1 bar.
NTP is set at 101.325 kPa but uses 20°C as the temperature
Answer:
3.329 g
Explanation:
First you need to determine the molar mass of H2S which is 34.1 g/mol.
With that we know that to find the moles of H2S we just divide the mass of sample with the molar mass.
3.54 g / 34.1 g/mol = 0.103812317 mol of H2S
This means that there is also 0.103812317 mol of sulfur since there is 1 mole of sulfur per 1 mole of H2S.
The molar mass of sulfur is 32.065 g/mol and to find the mass of sulfur you need to multiply the molar mass with the moles of the compound.
0.103812317 mol * 32.065 g/mol = 3.329 g of sulfur
Let me know if you get something else or if something is unclear in the comments so that we can figure it out.