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valentinak56 [21]
2 years ago
10

25 Points Please Help ASAP!! View Attached Image!! Will Mark Brainliest If All Are Answered!!

Chemistry
1 answer:
KIM [24]2 years ago
8 0

Answer:

Answers in explanation.

Explanation:

30. A (A chemical changes changes the chemical properties)

31. C (rusting is an example of a chemical change

32. B (A reaction requires energy, so some energy will be expelled)

33. B (Color change is an example of a chemical change)

34. A (The law of the conservation of mass: Mass and Energy cannot be created nor destroyed)

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If the distance between two objects of the same mass decreased the force of gravity between them would
Anni [7]

Answer:

The force of gravity between two objects will decrease as the distance between them increases.

Explanation:

4 0
3 years ago
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Calculate the standard molar enthalpy for the complete combustion of liquid ethanol (C2H5OH) using the standard enthalpies of fo
PSYCHO15rus [73]

Answer:

Explanation:

For the reaction

C2H5OH (l) + 3 O2(g) = 2CO2(g) + 3 H2O

We can calculate the  standard molar enthalpy of combustion using the standard enthalpies of formation of the species involved in the reaction according to Hess law:

ΔHºc =  2ΔHºf CO2 (g) + 3ΔHºfH2O(l)  - ( ΔHºf C2H5OH (l) - 3ΔHºfO2 (g) )

( we were not give the water state but we know we are at standard conditions so it is in its liquid state )

The ΔHºfs can be found in appropiate reference or texts.

ΔHºc =  2ΔHºf CO2 (g)+ 3ΔHºfH2O(l)  - (  ΔHºf C2H5OH (l) -+3ΔHºfO2 (g) )

= [ 2 ( -393.52 ) + 3 ( -285.83 ) ] - [(  -276.2 + 0 ) ] kJ

ΔHºc =  -1368.33 kJ

5 0
3 years ago
Which of the following is a reasonable way of describing the density of a gas at STP
dedylja [7]

Answer:the answer is a

Explanation:

8 0
2 years ago
How many grams of sodium chloride decompose to yield 15 grams of chlorine gas?
defon

Answer:

24.6g of NaCl

Explanation:

Expression of the reaction:

            2NaCl →  2Na  +  Cl₂

Given parameters:

Mass of Cl₂  = 15g

Unknown:

Mass of NaCl  = ?

Solution:

To solve this problem, we have to use mole relationships.

 Find the number of moles of the mass of the given specie;

    Number of moles  = \frac{mass}{molar mass}  

     Molar mass of Cl₂  = 2(35.5) = 71g/mol

   Number of moles  = \frac{15}{71}   = 0.21mole

Now;

 From the balanced reaction equation;

        1 mole of Cl₂ is produced from 2 moles of NaCl;

      0.21 mole of Cl₂ will be produced from 0.21 x 2 = 0.42mole of NaCl

So,

  Mass of NaCl = number of moles x molar mass

    Molar mass of NaCl  = 23 + 35.5 = 58.5g/mol

 Mass of NaCl  = 0.42 x 58.5 = 24.6g of NaCl

8 0
3 years ago
To make a 1.0L dilute of 0.5M from a stock solution of 12M, how much solution will be needed?
Cerrena [4.2K]

Answer:

V_{concentrated}=0.042L=4.2mL

Explanation:

Hello,

In this case, since in a dilution process the moles of the solute must remain unchanged, we use the volumes and molarities as shown below:

M_{diluted}V_{diluted}=M_{concentrated}V_{concentrated}

Clearly, the concentrated solution is 12M and the diluted solution is 0.5 M, thus, the volume of the concentrated solution we should take is:

V_{concentrated}=\frac{M_{diluted}V_{diluted}}{M_{concentrated}} =\frac{0.5M*1.0L}{12M}\\ \\V_{concentrated}=0.042L=4.2mL

Best regards.

6 0
3 years ago
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