Medical cold packs can use various chemicals in order to produce a cold compress to help reduce inflammation caused by injuries. Based on the accepted value in Question 1, how many grams of potassium chloride would have to be dissolved into 750 g of 20.0°C water to produce a 4.0°C solution? (Remember: specific heat of water is 4184 J/g·°C) 92 4.

We need 217.7 grams of KCl

Explanation:

Medical cold packs can use various chemicals in order to produce a cold compress to help reduce inflammation caused by injuries. Based on the accepted value of 17.2 kJ/mol, how many grams of potassium chloride would have to be dissolved into 750 g of 20.0 degree Celsius water to produce a 4.0 degree Celsius solution?

Step 1: Data given

Mass of water = 750 grams

Temperature = 20.0 °C

Temperature of the solution = 4.0 °C

Specific heat of water 4.184 J/g°C

Step 2: Calculate the heat

Q = m* c * ΔT

⇒with Q = the heat transfer = TO BE DETERMINED

⇒with m = the mass of water = 750 grams

⇒with c = the specific heat of water = 4.184 J/g°C

⇒with ΔT = The change of temperature = 16 °C

Q = 750 * 4.184 * 16

Q = 50208 J = 50.2 kJ

Step 3: Calculate moles KCl

Moles KCl = 50.2 kJ / 17.2 kJ/mol

Moles KCl = 2.92 moles

Step 4: Calculate mass KCl

Mass KCl = moles KCl * molar mass KCl

Mass KCl = 2.92 moles * 74.55 g/mol

Mass KCl = 217.7 grams

We need 217.7 grams of KCl

gravity causes stares to cluster i think so

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.