1) The volume of water used in crop irrigation is measured in acre-feet, where 1 acre-feet is the amount of water needed to cover 1 acre of land to depth of 1 foot. if there are 580 acres per square mile. how many cubic feet of water are in 1 acre-foot?

2) distances over land are measures in statute miles (5280 ft) but distances over H₂O are measured in miles, where i mile is equal to 1852 m. one knot = 1.0 mile per hour. an atlantic bluefin tuna can swim at speeds up to 40 statute miles per hour. how fast is this in knots?

3) Ag⁺ +Cl^- = AgCl, when 10 ml of 1 M AgNO3 is added to 10 ml 1 M NaCl at 25 C in a calorimeter, the temperature increased to 32.6 C. assuming that the specific heat of the aqueous mixture is 4.18 J/g C, that the density of the mixture is 1 g/ml and the calorimeter itself absorbs a negligible amount of heat, calculate the change in H (KJ/mol) for this reaction

 

#1. This problem needs a lot of conversion. We will first set the conversions we will need.

Given Conversions:

580 acres per square mile

Not given conversion:

1 mile = 5,280 feet

Convert the given info until you come up with the desired units.

Solution:

1 acre foot = 48,066.21 cubic feet

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#2 This problem needs a lot of conversion. We will first set the conversions we will need.

Given: 

speed = 40 statute miles/1 hour

knots = ?

Given Conversions:

1 statute miles = 5280 feet

1 mile = 1852 meter

1 knot = 1 mile/hour

Not given conversion:

1 meter = 3.28 feet

Convert the given info until you come up with the desired units.

Solution:

40 statute miles/hour = 34.76 knots

 

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#3 Given: 

10 ml of 1M AgNO3

10 ml of 1M NaCl

Change of T = 32.6-25 = 7.6 degrees C

specific heat = 4.18J/g C

density = 1g/ml

 

Step 1: Get the mass of each reactant

 

Since the mL of the reactants are given, we can use this to get the mass by using their concentration since...

 

M = mol/L

 

We need to convert first 10ml to L. So 10ml/1000 = 0.010 L

 

Thus...

 

Mole of AgNO₃ = 1M x 0.010L

Mole of AgNO₃ = 0.010 mole

 

Mole of NaCl = 1M x 0.010L

Mole of NaCl = 0.010 mole

 

We can get the mass by using the molecular mass of the substance.

 

AgNO3 MW = 169.87 g/mol

 

0.010 mole x 169.87 g/mol AgNO3 = 1.6987g of AgNO3

 

 

NaCl MW = 58.44 g/mol

 

0.010 mole x 58.44 g/mol NaCl = 0.5844 g of NaCl

 

 

Step 2: Find the enthalpy of the reaction

 

Use this equation:

 

ΔH = m x s x ΔT

 

where...

ΔH = enthalpy

m = mass of substances

s = specific heat

ΔT = change in temperature

 

So now we can solve this equation since we already know all of the values.

 

ΔH = m x s x ΔT

ΔH = (1.6987 g + 0.5844g) (4.18J/g C) (7.6 C)

ΔH = 72.53 J

Please see the attached file for the complete solution