morgan8222 said:I am doing a lab to find the concentration of copper in a penny. I am confused on how to find the concentration of copper in each solution I prepared. One solution for example:
2 ml of 0.080 M Cu(NO3)2
add 2 ml of concentrated ammonium hydroxide
dilute solution to 50 ml
Can someone help me out?
CrimpJiggler said:I'm confused. You have to find the concentration of copper in a penny. What has this got to do with adding 2 mL of NH4OH to Cu(NO3)2? Anyhow, you want to know how to find the concentration of copper in that 54 mL solution you prepared. Firstly, figure out how much copper is in 2 mL of 0.08M copper nitrate solution. M means moles per liter. This means there are 0.08 moles of copper nitrate in a liter of that solution. You only have 2 mL so how many moles are in that?
morgan8222 said:It is a total of 50 ml. Water is added to the solution until it is 50 ml.
0.080 M Cu(NO3)2 = 0.00016 moles in 2 ml
morgan8222 said:"Total concentration of copper" in this solution I prepared.
Concentration can be defined as the measure of amount of substance dissolved in known volume of a given solution. It is expressed in (amount in grammes of the substance per cubic centimete of solution when the mass concentration is concerned) gcm-3. It can also be expressed as in (amount in mole of substance per cubic decimeter of solution if the molar concentration is required ) moldm-3.sjb-2812 said:What is the definition of concentration?
chikis said:Concentration can be defined as the measure of amount of substance dissolved in known volume of a given solution.
I can infer from this defination that it is not easy to determine the concentration of a substance say copper in a penny unless the copper is disolved in a given volume of a solution. Your views are welcome. Thank you.
But like what I just said if any person want to determine the concentration of copper in a penny; at least that person have to dissolve that penny in a solution before it will be easy to find the concentration of copper in it. How about that?Borek said:Not bad, but not perfectly OK as well. Concentration can be also expressed as mass per mass (say 10% w/w NaCl solution means in each 100 g of solution there is 10 g of NaCl - whatever the volume is). It can be also expressed in terms of molar fraction, moles per mass of solvent (it is known as molality then) and so on.
You have sold me again! What does that w/w denote?
See above. There are other ways of expressing concentration that will be perfectly suitable to copper in penny. Mass per mass percentage would be my choice.
chikis said:But like what I just said if any person want to determine the concentration of copper in a penny; at least that person have to dissolve that penny in a solution before it will be easy to find the concentration of copper in it. How about that?
Borek said:Not bad, but not perfectly OK as well. Concentration can be also expressed as mass per mass (say 10% w/w NaCl solution means in each 100 g of solution there is 10 g of NaCl - whatever the volume is). It can be also expressed in terms of molar fraction, moles per mass of solvent (it is known as molality then) and so on.
You have sold me again! What does that w/w denote? You have not answered my question on yet. Please tell me what that w/w mean so that I will be following. Alright!
Concentration in a solution refers to the amount of solute (substance being dissolved) in a given amount of solvent (liquid in which the solute is dissolved).
Concentration is typically measured in units of moles per liter (M), grams per liter (g/L), or percentage (%).
The three main types of concentration in a solution are molarity, molality, and mass percent. Molarity is the number of moles of solute per liter of solution, molality is the number of moles of solute per kilogram of solvent, and mass percent is the mass of solute divided by the total mass of the solution multiplied by 100.
To calculate concentration, you will need to know the amount of solute and the total volume or mass of the solution. Then, use the appropriate formula for the type of concentration you are measuring. For molarity, the formula is moles of solute divided by liters of solution. For molality, the formula is moles of solute divided by kilograms of solvent. For mass percent, the formula is mass of solute divided by total mass of solution multiplied by 100.
Knowing the concentration in a solution is important because it can impact the properties and behavior of the solution. It can also affect the effectiveness of a solution in a particular application. Additionally, concentration is often used as a measure of the purity of a substance.