5. The heat of combustion of a sample of coal is 5500 cal/g. What quantity of this coal must be burned to heat 500.0 g of water from 20.0°C to 90.0°C?

6. The heat of combustion of a sample of coal is 5500 cal/g. What quantity of this coal must be
burned to heat 50.0 g of ice from 20.0°C to 90.0°C?

7. One gram of anthracite coal gives off 7000. cal when burned. How many joules is this?
How many grams of anthracite are required to raise the temperature of 4.0 L of water
from 20.0°C to 100.0°C?

8. A 500.0-g piece of iron is heated in a flame and dropped into 400.0 g of water at 10.0°C.
The temperature of the water rises to 90.0°C. How hot was the iron when it was first
removed from the flame? (Specific heat of iron is 0.473 J/gºC.)

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Nconcentration refers to the molar concentration of an ion in solution. it may be identical to, or greater or less than, the molar concentration of the compound containing the ion that was used to make the solution. for soluble salts, the molarity of a particular ion is equal to the molarity of that compound times the subscript for that ion. for example, 1 m of alcl3 is 1 m in al3+ and 3 m in cl−. 1 m of (nh4)2so4 is 2 m in nh4+ and 1 m in so42−. part a what is the concentration of k+ in 0.15 m of k2s? view available hint(s) nothing m m part b if cacl2 is dissolved in water, what can be said about the concentration of the ca2+ ion? view available hint(s) if is dissolved in water, what can be said about the concentration of the ion? it has the same concentration as the cl− ion. its concentration is half that of the cl− ion. its concentration is twice that of the cl− ion. its concentration is one-third that of the cl− ion. part c a scientist wants to make a solution of tribasic sodium phosphate, na3po4, for a laboratory experiment. how many grams of na3po4 will be needed to produce 550 ml of a solution that has a concentration of na+ ions of 0.700 m ? express your answer numerically in grams. view available hint(s) mass of na3po4 n a 3 p o 4 = nothing g provide feedback

Answer the questions about this reaction: nai(aq) + cl2(g) → nacl(aq) + i2(g) write the oxidation and reduction half-reactions: oxidation half-reaction: reduction half-reaction: based on the table of relative strengths of oxidizing and reducing agents (b-18), would these reactants form these products? write the balanced equation: answer options: a. 0/na -> +1/na+1e- b. nai(aq) + cl2(g) → nacl(aq) + i2(g) c. +1/na+1e- -> 0 /na d. -1/2i -> 0/i2+2e- e. no f. 4nai(aq) + cl2(g) → 4nacl(aq) + i2(g) g. 2nai(aq) + cl2(g) → 2nacl(aq) + i2(g) h. 4nai(aq) + 2cl2(g) → 4nacl(aq) + 2i2(g) i. nai(aq) + cl2(g) → nacl(aq) + i2(g) j. 0/cl2+2e -> -1/2cl- k. yes

At the current rate, a graph of carbon dioxide produced by fossil fuels over time would slope upward slope downward be horizontal be vertical