A student dissolves 11.6 g of sodium hydroxide (NaOH) in 250.g of water in a well-insulated open cup. He then observes the temperature of the water rise from 23.0 °C to 35.5 °C over the course of 4.4 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction: NaOH(s) Na (aq) + OH (aq) You can make any reasonable assumptions about the physical properties of the solution. Be sure answers you calculate using measured data are rounded to the correct number of significant digits. Note for advanced students: It's possible the student did not do the experiment carefully, and the values you calculate may not be the same as the knows and published values for this reaction. O exothermic Is this reaction exothermic, endothermic, or neither? endothermic X 5 ? neither If you said the reaction was exothermic or endothermic, calculate the amount of neat that was released or absorbed by the reaction in this case. Calculate the reaction enthalpy AW per mole of NaOH.

Put these processes of the water cycle in the correct order, starting at the point where the water is in the lake: 1. water evaporates into the atmosphere 2. rain, snow, or other precipitation falls 3. water collects into larger bodies of water 4. water vapor condenses into liquid water

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

The identities of substances are the same before and after which type of change