Stoich Flashcards
What are the steps in determination of limiting reactants or reagents
- Write a blanced chemical equation
- Caclulate the amount(moles) of both reactants
3.Using mole ratio, identify the limiting reagent reactant - Use the amount ( moles) of the limiting reagent and the mole ratio to determine the amount (moles) of the product
- Conver the amount (moles) of the product back to the desired units
- Check sig figs.
What is formula for volume not in slc
V= nRT/p
What is Specific heat capacity
Specific heat capacity of a substance is the amount of energy needed to raise the temperature of 1g of the substance by 1°C
What units is SPECIFIC Heat capacity in?
J g-1 °C-1 or J g-1 °K-1
Why does water have a high specific heat capacity than oil
Because the hydrogen bonds between water moldecules are STRONGER than the dispersion forces between oil molecules
Ways to reduce heat loss during calorimetry experiments
1.Putting a lid on the calorimeter
2.Insulating the beaker of water with flameproof material
3.Placing insulation around burning food, but maintaining sufficient oxygen supply for burning the food
4.Reduce the distance of the flame
What type of error would the factor of heat loss from calorimetry be
Systematic error as it affects accuracy
what is the formula for energy released per gram
qtotal= m x energy per gram
what is the energy released in combustion per mole
q total = n x AH (heat of combuhhh)
What is a calorimeter
A thermal insulated containter that tries to minimise the heatloss
Almost all heat transfers are to or from the measured volume of water
true or false
true
What are the main steps of calorimetry
- Calibration
- Experiment
What is the calibration of calorimeter
Hoe much energy is required to raise the tempreature of the whole system(as all parts of the system will absorb energy) by 1*C for THAT calorimeter used in the experiment
What is the eq for CF
and its units
CF= E(cal)/ delta T(cal)
E is the amount of energy to the CM during calib
The units for CF- JC-1 or kJC-1
Whats in a solution calorimetry
Thermometer
Mechanical or noram stirrer
Electic heater for calibrating the calorimeter
Insulated container
Glass bulb contating second reactant
Solution of one reactant
What is the point of the stirrer in calorimetry
Uniform distrubtion of heat and allows for reactants to mix evenly
if i put 100j of energy into the calorimeter and the change in tempreature is 5 degress. whats the CF
20j/c
meaning for every 1 degree, 20 j of energy is required
What are the two main ways of calibrating a calorimeter
1.Electrical calibration
2.Chemical calibration
what cant the solution calorimeter measure?
energy of content of food or a fuel as the reaction is combustion and requires to burn in oxygen.
What is the solution calorimeter used for
Ussed to measure enthalpy changes in chemical reactions such as dissolving or acid-base reactions while minimsing heat loss
Why is calibration of a calorimeter required?
So that the data supplied is more accurate and the heat loss is minimised
What is electircal calibration
Supplying a measured amount of electircal energy to the calorimeter system to increase the thermal energy and asssuming that all of the energy is converted to heat energy
What is the electircal calibration energy formula ( include units)
Energy (Joules) = voltage (volts) × current(amperes) × time(seconds)
E = V × I × t
Why after the calorimeter heater is turnt off or even during the tempreature may drop?
As there is heat loss occuring due to the calorimeter not being properly insulated.
