## You have done some mixing and measuring & made graphs to calibrate the conductivity meter.... now we can use all that....

**Does the tide affect the salinity of the water in the stream or the Maitai ?**

**Does the tide affect the salinity of the water in the stream or the Maitai ?**

**Conductivity Calibration graph**

**Theory: notes etc**

*(hmmm old site gone)*

**Theory: research task**

**Our 2016 data: HERE**

## Potato fish data

Salinity Investigation

To carry out a practical investigation looking at the effect of the tide on the salinity of the stream or Maitai

collect samples, measure conductivity (with the machine), calculate salinity (using the calibration graph) record your data

Note: we were collecting samples about 1 hour after high tide

· Process your data:

- finish using the calibration graph to find the salinity of each sample (average where we have 2 readings)

- grab (

- add the salinity data to the Google image, show surface and bottom salinities at each site

· Research …. What is a salt wedge?

Figure out....How far down does the salt wedge go in our study area?

·

**Aim:**To carry out a practical investigation looking at the effect of the tide on the salinity of the stream or Maitai

**Method**collect samples, measure conductivity (with the machine), calculate salinity (using the calibration graph) record your data

Note: we were collecting samples about 1 hour after high tide

**Results**· Process your data:

- finish using the calibration graph to find the salinity of each sample (average where we have 2 readings)

- grab (

*Snipping Tool or similar*) a Google earth image of the stream / Maitai and identify our sample locations- add the salinity data to the Google image, show surface and bottom salinities at each site

· Research …. What is a salt wedge?

Figure out....How far down does the salt wedge go in our study area?

·

**Write your report, include:**- title
- aim
- method (maybe include some photos here too)
- results (our data processed and added to a Google map/image to show salinity)
- and discussion of the results (effect of tide, salt wedge?)
- add finished report to the dropbox

## stream investigation

## The problem of living in an area where the salinity changes

**A red onion cell in salt water**

*Explain what has happened to it*

*Describe our potato fish experiment*

*Here is a link to our data and graph*

Old website stuff:

one pair = 2 things

one dozen = 12 things

one score = 20 things

one gross = 144 things

Moles ,n = grams of substance / atomic (or molecular) mass

n = g/Ar

Example:

H = 1 gram = 1 mole = 6.02 x 1023 atoms H

He = 4 grams = 1 mole = 6.02 x 1023 atoms He

Na = 23 grams = 1 mole = 6.02 x 1023 atoms Na

8 g of H is.....

8 g of He is.....

8 g of O is.....

14

Si

28.08

Silicon

one mole of Si atoms = 28.08 g

Molecular weight or Molar Mass is the sum of the masses of all the atoms in a compound. It is the mass, in grams, of one mole of a compound.

Example: H2O, water. One mole contains:

1 mole of O atoms = 1 x 16 = 16 grams

2 moles of H atoms = 2 x 1 = 2 grams

So the molar mass of H2O = 16 + 2 =

Example: Na2CO3, sodium carbonate. One mole contains:

1 mole of C atoms = 1 x 12 = 12 grams

2 moles of Na atoms = 2 x 23 = 46 grams

3 moles of O atoms = 3 x 16 = 48 grams

So the molar mass of Na2CO3 = 12 + 46 + 48 =

Practice Calculating Molar Masses

Calculate the molar masses for each formula.

H

CO

NaCl

Na

C

Cu(NO

(NH

Or try this

http://www.chem.vt.edu/RVGS/ACT/notes/molar_mass.html

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This is the number of moles of the solute dissolved in one litre of the solution.

Concentration = no. of moles / volume (L)

Conc = n/L

Example 1: A 1 molar (1 M) solution of HCl contains 36.5 g of HCl per liter of solution, since 36.5 g is the molecular weight of HCl, 36.5 g/mole.

Example 2: A 0.5 molar (0.5 M) solution of HCl contains 18.25 g of HCl per liter of solution, since 18.25 g is half the molecular weight of HCl, 36.5 g/mole.

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Density

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(link removed for now)

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*What is a Mole*__Just as__:one pair = 2 things

one dozen = 12 things

one score = 20 things

one gross = 144 things

**one mole = 6.02 x 1023 things****that is...... 600 000 000 000 000 000 000 000****The number of people on earth is about 6 000 000 000****t****hat is a****heck of a lot less than****a single mole !!!!!!****Q**What chemical quantities contain one mole (ie 6.02 x 1023 ) things?**Ans**The atomic mass (in grams) of a substance contains one mole of atomsMoles ,n = grams of substance / atomic (or molecular) mass

n = g/Ar

Example:

H = 1 gram = 1 mole = 6.02 x 1023 atoms H

He = 4 grams = 1 mole = 6.02 x 1023 atoms He

Na = 23 grams = 1 mole = 6.02 x 1023 atoms Na

8 g of H is.....

8 g of He is.....

8 g of O is.....

*Atomic and Molecular Weights**Atomic weight*is the*averaged*mass of elements. They appear on the periodic table in the box for each element.14

Si

28.08

Silicon

one mole of Si atoms = 28.08 g

Molecular weight or Molar Mass is the sum of the masses of all the atoms in a compound. It is the mass, in grams, of one mole of a compound.

Example: H2O, water. One mole contains:

1 mole of O atoms = 1 x 16 = 16 grams

2 moles of H atoms = 2 x 1 = 2 grams

So the molar mass of H2O = 16 + 2 =

__18 grams__Example: Na2CO3, sodium carbonate. One mole contains:

1 mole of C atoms = 1 x 12 = 12 grams

2 moles of Na atoms = 2 x 23 = 46 grams

3 moles of O atoms = 3 x 16 = 48 grams

So the molar mass of Na2CO3 = 12 + 46 + 48 =

__106 grams__Practice Calculating Molar Masses

Calculate the molar masses for each formula.

H

**2**CO

**2**NaCl

Na

**2**SO**4**C

**12**H**22**O**11**Cu(NO

**3**)**2**(NH

**4**)**2**SO**4**Or try this

http://www.chem.vt.edu/RVGS/ACT/notes/molar_mass.html

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*Solutions**Concentration*This is the number of moles of the solute dissolved in one litre of the solution.

Concentration = no. of moles / volume (L)

Conc = n/L

Example 1: A 1 molar (1 M) solution of HCl contains 36.5 g of HCl per liter of solution, since 36.5 g is the molecular weight of HCl, 36.5 g/mole.

Example 2: A 0.5 molar (0.5 M) solution of HCl contains 18.25 g of HCl per liter of solution, since 18.25 g is half the molecular weight of HCl, 36.5 g/mole.

**Q 1 Find the conc. if 5.8g of NaCl is dissolved in 1L of water?****Q 2 Find the conc. if 5.8g of NaCl is dissolved in 200mL of water?****Q 3 Find the conc. if 40g of NaOH is dissolved in 10L of water?****Q 4 Find the conc. if 0.40g of NaOH is dissolved in 100mL of water?****Q 5 How much NaCl is needed to give 500mL of a 0.25 mol/L solution?****Now let’s evaporate some sea water…..what for?****Is there a better way…I think so!**back to top

**Salinity work.****Making up solutions for calibrating the conductivity meter****Now to our investigations....****Salinity of the coastal water 2007**Density

**Seen one of these on a ship?****'Swimming' in the dead sea**back to top

**Now to more investigations....****Salinity of the coastal water(Wed) 2007****Salinity of the coastal water(Thur) 2007****salt wedge... http://www.oceanservice.noaa.gov/education/kits/estuaries/media/supp_estuar05a_wedge.html****Maitai Channel salt wedge**(link removed for now)

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