help with concentration and dilution

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Hello, can somebody help me with these exercices, please give me the steps and the formula (with all the x and y filled) for each different type of question and please show the exercices that are alike when you explain? These we're originaly in french and I will translate.

 

1- From a solution of K2Cr2o7 with a concentration of 2% ( 2 g/ 100 ml of solution) you must prepare:

a) 100 ml of a solution 5 times less concentrated

b)50ml of a solution 4 times less concentrated

 

2- From a 450 ml solution of CuSO4 x 5h2O concentred at 30g/L, are you capable of making the concentrations that follows? If yes, explain your steps.

a) 50 ml of a solution that has concentration is 15g/L

b) 100 ml of a solution that has concentration 10g/L

 

3- Jean-Francois works in a industry. We give him 500 ml of a solution CaCl2 concentred at 20g/L. He must prepare the following solutions. (Explain your steps)

a) 60 ml of a solution that is 4 times less concentrated

b) 100 ml of solution concentrated at 4g/L.

 

4- We must prepare by dilution 16 ml of a solution of Co(NO3)2 concentred at 15% from a solution of Co(NO3)2 with a concentration of 5%. What must he do??

 

5- What is the concentration of 120 ml a solution of Co(NO3)2 prepared by dilution from 24 ml of a solution of Co(NO3)2 concentred at 15%??

 

 

6.We are using peroxyde to color. To economise, we get a solution concentred at 60% (v/v). We must prepare 1 L of peroxyde at 30%. What must we do to not waste peroxyde?

 

7.Pierre buys 400 ml of frozen lemonade. He notices that he must add 4 containers of water to dilute the frozen product, What must he do if he wants to make a glass of 300 ml of his drink?

 

8. The technician prepared 200 ml of a solution of NaOH with a concentration of 80 g/l. Since the hydroxide of sodium is strong base which represents danger to the students this concentration has to be diluted to a concentration of 8g/L.

a) What is the volume of the solution after?

b) What quantity of water we must dissolve for this solution

 

9. We ask to prepare 300 ml of a solution of KOH with a concentration of 28g/l What quantity of this base we must dissolve preparer cette solution.?

 

10.afin de neutraliser un acide, on demande de preparer 400 ml de solution de NaOH a une concentration de 20g/l. What quantity of dhydroxyde of sodium we have to use to prepare this solution?.

 

11.After preparing 150 ml of salty water with a concentration of 50 g /l, a technicien wants to dilute. He wants to have a solution of a concentration of 5g/l.What quantity of water must he add to the original solution??

 

12. We want to prepare 200 ml of a solution of CuSO4 with a concentration of 4g/l from a solution concentred at 20 g/l. What volume of the original solution must we use?

 

13. a 20 ml of a solution of salty water has 40 g/ L, we add 80 ml of water, what will be the concentration?.

 

14.We prepare 2L of soup and we notice that it is twice has salty. What quantity of water must we add to make it acceptable?.

 

15.The vinagar is a solution acetic acid at 5%(v/v).show how we can make vinaigar from 500 ml of a solution of acetic acid at 30% (v/v).

 

17.The vinagar is a solution acetic acid at 5%(v/v). What quantity of a solution of acetic acid at 40% (v/v) Must we use to prepare 1L of vinaigar??

 

18. a bag of powdered juice lets us prepare 1,5 l of a drink. If the bag of 25 g of sugar what is the concentration of sugar this contains drink in g/L??

 

19.A student tastes a drink prepared ealier and finds it too sweet. He decides to make the volume to 2L. What is the concentration now of the sugar now?

 

20.A solution of analgesique contains 1,5g dacetaminophene per 150 ml. What is the concentration of this analgesique in g/L??

 

21. We make react of lacide chlorydrique (HCL) with dihydroxyde de calcium Ca(OH)2 . We obtain of dichlorure de calcium, CaCl2 and water ,H20.

a)write the equation of this reaction.

b) what is the weight of CaCl2 made if 500 ml of acide of 0,4 mol/l was used.

 

22.Some cars use as combustilble makes natural gaz, methane (CH4), it makes h2o and co2.

-Write the equation of this reaction.

-if the car uses 320 g of methane what weight of co2 and water will be produce

-how much oxygene must we burn to 160g of methane

-if 80 moles of molecules of eau was produced how much molecules of co2 was also produced?

 

23.I want to prepare 50ml of a solution of which the concentration is 10g/400ml, what is the quantity I want to prepare 50 ml of a solution with a concetration of 10g/400 ml, How much quantity of solute is necessary? Give the steps.

 

24. what quantity of sugar must I use to prepare 500 ml of a liquid solution (10%)?

 

25.What are the steps necessary to prepare 800ml of a solution with the concentration of 37.5g/

 

26.what is the quantity of solute must use to prepare 150ml of a solution with the concentration of 233.33g/100ml

 

27.what is the quantity of solute necessary to prepare 1L of a solution of 1g solute for 40ml of solution

 

28.what is the quantity of solute necessary to prepare 30ml of a solution with a concentration of 26.67 in 100ml. Include the steps of preparation also.

 

Please answer it took me along time to translate by myself all this.

 

Just asking is the answer to 1. a. 80ml? I did 2xV1=0.4x100 the answer is 20ml so then I did 100-20=80