A. False. If it is high tide in one place on Earth, the place exactly opposite to it will also have a <em>high</em> tide.
The gravitational attraction of the Moon and the inertia of the oceans cause <em>two tidal bulges </em>on opposite sides of the Earth.
B. True. Cassini used flybys of Venus, Earth and Jupiter as slingshots to reach Saturn.
C. True. The whole solar system moves around the galaxy.
D. True. If a planet’s gravity is not strong enough, the molecules in its atmosphere will have enough kinetic energy to escape into space.
E. False. The <em>mass of an object is constant</em>, but its <em>weight changes</em> according to the gravity of the planet.
F. False. To find the mass of an object, <em>divide</em> its weight by gravity.
or weight = mass × gravity
∴ <em>Mass = weight/gravity
</em>
Answer:
2.28 × 10^-3 mol/L
Explanation:
The equation for the equilibrium is
CN^- + H2O ⇌ HCN + OH^-
Ka = 4.9 × 10^-10
KaKb = Kw
4.9 × 10^-10 Kb = 1.00 × 10^-14
Kb = (1.00 × 10^-14)/(4.9 × 10^-10) = 2.05 × 10^-5
Now, we can set up an ICE table
CN^- + H2O ⇌ HCN + OH^-
I/(mol/L) 0.255 0 0
C/(mol/L) -x +x +x
E/(mol/L) 0.255 - x x x
Ka = x^2/(0.255 - x) = 2.05 × 10^-5
Check for negligibility
0.255/(2.05 × 10^-5) = 12 000 > 400. ∴ x ≪ 0.255
x^2 = 0.255(2.05 × 10^-5) = 5.20 × 10^-6
x = sqrt(5.20 × 10^-6) = 2.28 × 10^-3
[OH^-] = x mol/L = 2.28 × 10^-3 mol/L
<span>Opening a can of paint requires a screwdriver or other machine to pry open the lid. The screwdriver affect the force applied to opening the lid. The answer is : </span><span>B. It increases the applied force and changes its distance and direction.</span>
Heat capacity of aluminium = 0.900 J/g°C
While heat capacity of water = 4.186 J/g°C
Heat = heat gained by water + heat gained by aluminium
Heat gained by water = 100 × 4.186 × 30.5
= 12767.3 Joules
Heat gained by aluminium = 15 × 0.9 × 30.5
= 411.75 Joules
Heat required = 13179.05 Joules or 13.179 kJoules
