What is the density of a 5 mL sample of 1.95g of Gold

When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical change or a

Degger [83]

Answer: Chemical change

Explanation:

Physical change is a change where there is a change in size , shape etc and no new products are formed.

Chemical change is a change where there is a change in chemical composition as new products are formed.

Example: Formation of soap and glycerin from fat and sodium hydroxide is a chemical change as the chemical bonds are getting rearranged to form new products.

8 0

3 years ago

Need help with this problem asap

ehidna [41]

Answer:

Is that all of the problem??

Explanation:

8 0

3 years ago

Which best describes how the sun rotates?

son4ous [18]

D.The sun does not rotate

7 0

4 years ago

Explain how a pure metal is held together.

Marta_Voda [28]

A piece of pure metal, like copper or iron, comprises metal atoms, which are surrounded by electrons of moving force which drift free from each other's metal. The attraction between free - floating valence electrons and positive metal ions results in metallic bonds.

4 0

4 years ago

The density of toluene (C7H8) is 0.867 g/mL, and the density of thiophene (C4H4S) is 1.065 g/mL. A solution is made by dissolvin

nadya68 [22]

Answer:

(a) 0.039

(b) 0.384 M

(c) 0.373 M

Explanation:

We have the following data:

d(C₇H₈) = 0.867 g/mL

d(C₄H₄S) = 1.065 g/mL

V(C₇H₈) = 250.0 mL

mass(C₄H₄S) = 8.10 g

(a) The mole fraction of C₄H₄S in the solution is the number of moles of C₄H₄S divided into the total moles of the solution:

X(C₄H₄S) = moles C₄H₄S/ total moles

To calculate the moles, we need the molecular weight (MW) of each compound:

MW(C₄H₄S) = (4 x 12 g/mol) + (4 x 1 g/mol) + 32 g/mol = 84 g/mol

MW(C₇H₈) = (7 x 12 g/mol) + (8 x 1 g/mol) = 92 g/mol

Thus, we calculate the moles of C₄H₄S by dividing the mass into the MW(C₄H₄S):

moles C₄H₄S = mass(C₄H₄S)/MW(C₄H₄S)= 8.10 g/(84 g/mol) = 0.096 moles

Then, we have to calculate the moles of C₇H₈. First, we need the mass, obtained from the product of the density by the volume:

mass(C₇H₈)= d(C₇H₈) x V(C₇H₈) = 0.867 g/mL x 250.0 mL = 216.75 g

Thus, we divide the mass of C₇H₈ into the MW to calculate the moles of C₇H₈:

moles C₇H₈ = mass(C₇H₈)/MW(C₇H₈) = 216.75 g/(92 g/mol) = 2.35 moles

The total moles is obtained from the addition of the moles of the solute (C₄H₄S) and the solvent (C₇H₈):

total moles = moles C₄H₄S + moles C₇H₈ = 0.096 moles + 2.35 moles = 2.45 moles

Finally, we calculate the mole fraction of C₄H₄S:

X(C₄H₄S) = moles C₄H₄S/ total moles = 0.096 moles/2.45 moles = 0.039

(b) The molarity of C₄H₄S is calculated as follows:

M(C₄H₄S) = moles C₄H₄S/1 liter solution

Assuming that the total volume of the solution is the volume of solvent (C₇H₈), we calculate the molarity of C₄H₄S by dividing the moles into the volume of solvent in liters:

V(C₇H₈) = 250.0 mL = 0.250 L

M(C₄H₄S) = 0.096 moles/(0.250 L) = 0.384 mol/M = 0.384 M

(c) Assuming that the volumes of solute and solvent are additive, we can add the volumes of C₄H₄S and C₇H₈. First, we need the volume of C₄H₄S, which can be calculated from the mass and density:

V(C₄H₄S) = mass(C₄H₄S)/ d(C₄H₄S) = 8.10 g/(1.065 g/mL) = 7.606 mL = 0.0076 L

Now, we add the volumes:

total volume = V(C₇H₈) + V(C₄H₄S) = 0.250 L + 0.0076 L = 0.2576 L

Finally, we recalculate the molarity of C₄H₄S:

M(C₄H₄S)= moles C₄H₄S/ total volume = 0.096 moles/0.2576 L = 0.373 M

7 0

3 years ago