Which of the following is an example of a mixture? Option 1: Pure water Option 2: The air in your room Option 3: Gold Option 4: All of the above

Answer:

A. Diffusion

Explanation:

A.Diffusion  - this is correct. Diffusion is the process where small molecules enter the cell by moving from a high concentration to a low concentration through a semi-permeable membrane.

B.Exocytosis  - this is incorrect. Exocytosis is a cell transport mechanism where the cell uses a system of vesicles to transport cargo outside of the cell. The vesicles fuse to the cell membrane and deliver the cargo outside.

C.Osmosis  - this is incorrect, osmosis is a type of diffusion specific to water molecules

D.Endocytosis - this is incorrect. Endoocytosis is a cell transport mechanism where the cell uses a system of vesicles to transport cargo into the cell. The cell membrane engulfs the molecules and brings them into the cell via the vesicle

Answer:

           Molecules Collide more frequently

Explanation:

The factors which effect the rate of reactions are as follow,

                  Concentration:

                                           Increase in concentration of reactants will increase the number of reactants per unit volume. Therefore, the probability of collisions will increase hence, it will result in the increase in yield.

                  Temperature:

                                       Increase in temperature increases the kinetic energy of reactants. Therefore, the increase in velocity of reactants results in the collisions with high energy. It makes it feasible for reactants to attain the optimum energy (activation energy) to convert into products with good yield.

                 Surface Area:

                                      The reactants in grinded / powder form reacts fast as compared to solid form. In fact, grinding results in increase of the surface area of reactants. Greater surface area increases the probability of reactants to colloid. Hence, increases the yield.

Conclusion:

                   As shown, all the given factors are related to collisions of molecules or atoms hence, the option selected is the correct option.

Answer:

$182 is the value of the gold in the coin

Explanation:

Diameter is 2r, the ratio of the coin is = 1.62cm / 2 = 0.81cm

Following the formula of the volume of the coin:

V = π r² h

V = π*(0.81cm)²*0.085cm

V = 0.172cm³ = mL

As the density of the gold is 19.32g/mL, the mass of 0.1752mL of gold is:

0.1752mL * (19.32g / mL) =

3.385g is the mass of the coin

As the price of the gold is $53.90 / g, the value of the gold in the coin is:

3.385g * ($53.90 / g) =

$182 is the value of the gold in the coin

Final answer:

To find the value of the gold in the coin, calculate its volume using the formula for the volume of a cylinder. The value of gold in the coin is $185.37.

Explanation:

To calculate the value of gold in the coin, we need to find its volume first using the formula for volume of a cylinder:

The radius (r) of the coin is half its diameter, so it is 0.81 cm. The height (h) is 0.085 cm. Plugging in these values, we can find the volume of the coin. Next, we calculate the mass of the gold in the coin using its density and the volume we just calculated. Finally, we multiply the mass by the price per gram of gold to find the value of the gold in the coin.

The volume of the coin is:

= 0.178 cm3.

The mass of the gold is:

m = density x volume

= 19.32 x 0.178

= 3.443 g.

The value of the gold in the coin is the value as -

= mass x price per gram

= 3.443 g x $53.90/g

= $185.37.

Learn more about value of gold in a coin here:

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