Answer:
Q = 270 Joules (2 sig. figs. as based on temperature change.)
Explanation:
Heat Transfer Equation of pure condensed phase substance => Q = mcΔT
Mixed phase (s ⇄ l melting/freezing, or l ⇄ g boiling/condensation) heat transfer equation => Q = m∙ΔHₓ; ΔHₓ = phase transition constant
Since this is a pure condensed phase (or, single phase) form of lead (Pb°(s)) and not melting/freezing or boiling/condensation, one should use
Q = m·c·ΔT
m = mass of lead = 35.0g
c = specific heat of lead = 0.16J/g°C
ΔT = Temp change = 74°C - 25°C = 49°C
Q = (35.0g)(0.16J/g·°C )(49°C) = 274.4 Joules ≅ 270 Joules (2 sig. figs. as based on temperature change.)
Make a ball of clay and embed small beads throughout it. The plum pudding model.
Answer:
B
Explanation:
It is a gas and therefore according to particle model of matter it has large spaces between them and does not have a definite shape
Answer:
The proportion of dissolved substances in seawater is usually expressed in ppm, ppb or ppt
Explanation:
The concentration of very diluted solutions should be expressed in parts per million, billion or trillion.
ppm = mass from the solute . 10⁶ / mass or volume of the solution
ppb = mass from the solute . 10⁹ / mass or volume of the solution
ppt = mass from the solute . 10¹² / mass or volume of the solution
ppm = mg/kg, μg/g, μg/mL → These are the units
ppb = ng/g
ppt = pg/g
If molecules are in a closed container then we expect the pressure to increase as the kinetic energy increases. This is because the atoms of an element collide with the walls of the container and increase the pressure.
If we use the formula 
, where P is the pressure, V is the volume, n is the number of moles, R the ideal gas constant and T is the temperature. According to the formula, P is directly proportional to temperature. An increase in temperature leads to an increase in pressure.
Since we know that temperature is the average kinetic energy of molecules present. It means as we increase the temperature we increase the kinetic energy of the molecules which in turn leads to an increase in the pressure.
