Answer:
Exothermic reaction for the HCl, endothermic reaction for the water
Explanation:
Heat was lost by HCl as its temperature lowered, so it was an exothermic reaction for the HCL.
Heat was gained by water as its temperature increased, so it was an endothermic reaction for the water.
m = Mass of water = 100 g
c = Specific heat of water = 
= Change in temperature of water = 
Heat is given by
Heat gained by water is .
Answer:
The cost of electricity for 100 W power bulb = $ 32.85
Cost of electricity for 0.025 W fluorescent bulb = $ 8.2125
Explanation:
Cost of electricity = $ 0.18 per KW-H
Time = 5 hour per day
Bulb power = 100 W = 0.1 KW
Fluorescent bulb power = 25 W = 0.025 KW
(a) Cost of electricity for 100 W power bulb
0.1 × 5 × 365 × 0.18 = $ 32.85
(b) Cost of electricity for 0.025 W fluorescent bulb
0.025 × 5 × 365 × 0.18 = $ 8.2125
Therefore the cost of electricity for 100 W power bulb = $ 32.85
Cost of electricity for 0.025 W fluorescent bulb = $ 8.2125
Answer:
there are 6 significant figures in 107.051
Answer:
Explanation:
The element V forms acidic oxide so it must be non- metal because oxides of non metal forms acidic oxide like sulphur ( s ) or chlorine ( Cl₂ )
sulphur forms SO₂ or SO₃ . Chlorine forms acidic oxide like Cl₂O₇ , Cl₂O₃ etc
These oxides are covalent compounds .
So V may have 6 or 7 electrons in the outermost orbit .
Hence option D is the right answer.
Answer:
25.8
Explanation:
Let's write the reaction between magnesium-phosphide and potassium:
Mg3P2 + K = Mg + K3P
And now let's balance this equation:
Mg3P2+6K=3Mg+2K3P
We see that the ratio of magnesium-phosphide and potassium is 1:6, which means that for every mole of magnesium-phosphide there need to be 6 moles of potassium.
Since we have 4.3 moles of Mg3P2, there need to be 6 • 4.3 = 25.8 moles of potassium.
