Answer: The correct option is 3.
Explanation: Radioisotopes that emit alpha-particles are termed alpha-emitters. These isotopes undergo alpha-decay.
Those radioisotopes that emit beta-particles 
are called beta-emitters. They undergo beta-minus decay, in which a neutron converts to a proton and an electron.
Isotopes that emit positrons 
are known as positron-emitters, undergoing beta-plus decay where a proton becomes a neutron.
From the options given,
Option 1: All three isotopes undergo beta-minus decay.
Option 2: Cs-137 and Tc-99 undergo beta-minus decay.
Fr-220 undergoes alpha-decay.
Option 3: Kr-85 undergoes beta-minus decay.
Ne-19 undergoes positron decay.
Rn-222 undergoes alpha decay.
Option 4: All three isotopes undergo beta-minus decay processes.
Therefore, the correct choice is 3.
Answer:
81°C.
Justification:
We can arrive at this conclusion using the formula:
Q = m.c.ΔT,
where Q denotes the heat lost by water (Q = - 1200 J).
m represents the mass of water (m = 20.0 g).
c indicates the specific heat of water (c = 4.186 J/g.°C).
ΔT signifies the difference between the starting temperature and the final temperature (ΔT = final T - initial T = final T - 95.0°C).
Given Q = m.c.ΔT
It follows that (- 1200 J) = (20.0 g)(4.186 J/g.°C)(final T - 95.0°C ).
(- 1200 J) = 83.72 final T - 7953.
∴ final T = (- 1200 J + 7953)/83.72 = 80.67°C ≅ 81.0°C.
Consequently, the correct answer is: 81°C.
It's important to remember that 1 pint equals 473.1765 mL, therefore 11 pints amounts to 5204.9415 mL.
We can formulate a proportion based on the problem statement
(85 mg glucose/ 100 mL) times (1 g/ 1000 mg) = 4.4242 grams of glucose
Ca3(PO4)2 is the correct formula.
Diethyl ether (DTH) and Tetrahydrofuran (THF).
Clarification:
- Grignard reactions react with water, resulting in the formation of alkanes. The presence of water leads to rapid decomposition of the reagent.
Therefore, solvents like anhydrous diethyl ether or tetrahydrofuran (THF), as well as poly(tetramethylene ether) glycol (PTMG), are used in experimental procedures to limit the exposure of Grignard reagents to air and moisture.
These solvents are chosen because the oxygen they contain stabilizes the magnesium reagent.
THF is a stable compound.
