The right answer is the first molecule (3-methyl-butan-2-one).
There are many bands around 2900-3000 cm-1 proving the presence de C-H bound.
There an intense band in 1700 cm-1 proving the presence of C=O.
There's no band proving the presence of aromatic structure, C=C bond nor C-N bond.
The granite block transferred <u>4080 J</u> of energy, and the mass of the water is <u>35.8 g</u>.
1. <em>Energy from granite block
</em>
The formula for the heat (<em>q</em>) transferred is
<em>q = mC</em>Δ<em>T</em>
<em>m</em> = 126.1 g; <em>C</em> = 0.795 J·°C⁻¹g⁻¹; Δ<em>T</em> = <em>T</em>_f – <em>T</em>_i = 51.9 °C - 92.6 °C = -40.7 °C
∴ <em>q</em> = 126.1 g × 0.795 J·°C⁻¹g⁻¹ × (-40.7 °C) = -4080 J
The granite block transferred 4080 J.
2. <em>Mass of water
</em>
<em>q = mC</em>Δ<em>T
</em>
<em>m = q</em>/(<em>C</em>Δ<em>T</em>)
<em>q </em>= 4080 J; <em>C</em> = 4.186 J·°C⁻¹g⁻¹; Δ<em>T</em> = <em>T</em>_f – <em>T</em>_i = 51.9 °C – 24.7 °C = 27.2 °C
∴ <em>m</em> = 4080 J/(4.186 J·°C⁻¹g⁻¹ × 27.2 °C) = 35.8 g
The mass of the water is 35.8 g.
The half-life of Plutonium−239, t1/2 is 2.41 × 10⁴<span> yrs
time taken to reach tolerable level = seven half-lives
= 7 x t1/2
= 7 x </span>2.41 × 10⁴ yrs
= 168700 yrs
= 1.687 x 10⁵ yrs
Hence, the period of time that <span>Plutonium-239 must be stored is </span>1.687 x 10⁵ years.
Can vary. Carbon is used quite commonly, and extracts metal oxides, works with zinc, iron, tin, lead and copper.
