Insulation materials with higher thicknesses have lower long-term thermal conductivity values in general. The density of rigid polyurethane foam (PUR/PIR) used for building thermal insulation typically ranges from 30 to 45 kg/m3. For some applications, however, it can achieve 100 kg/m3.
I would say they design and build things.
Answer:
About 512 g.
Explanation:
We are given a sample of P₂Cl₅ that contains 179 grams of phosphorus, and we want to determine the grams of chlroine that is present.
Thus, we can convert from grams of phosphorus to moles of phosphorus, moles of phosphorus to moles of chlorine, and moles of chlorine to grams of chlorine.
From the formula, there are two moles of P for every five moles of Cl. The molecular weights of P and Cl are 30.97 g/mol and 35.45 g/mol, respectively. Hence:

In conclusion, there is about 512 grams of chlorine present in the sample.
Alternatively, we can mass percentages. The mass percent of phosphorus in P₂Cl₅ is:

Because there are 179 grams of phosphorus, the total amount of sample present is:

Therefore, the amount of chlorine present is 691.1 g - 179 g, or about 512 g, in agreement with our above answer.
Answer: Radon-222 is generated in the uranium series from the alpha decay of radium-226, which has a half-life of 1600 years. Radon-222 itself alpha decays to polonium-218 with a half-life of approximately 3.82 days, making it the most stable isotope of radon. Its final decay product is stable lead-20