1. A 36.0 g sample of liquid water is initially at 10.0 °C. How many kJ are required to turn it into steam at 200.0 °C? 2. How much energy is required to heat 125.0 g of ice from -15.0 °C to liquid water at 35.0°C?

3. How many kJ are needed to heat 300.0 g of ice at -5.00°C into steam at 100.°C?

4. Calculate the amount of energy removed to cool 50.0 g of steam at 135.0 °C to ice at -20.0 °C.

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

b

explanation: