Reagent Preparation Quiz Part 2

To make a 1:4 dilution of bleach solution, you need to mix 1 part of bleach with 4 parts of water. Since the total volume of the dilution needed is 10mL, you can calculate the amount of bleach needed by dividing the total volume by the sum of the parts in the dilution ratio (1+4=5). Therefore, 10mL/5 = 2mL. However, since the question asks for the amount of bleach needed, we need to consider that the dilution already contains 2 parts of bleach, so we subtract that from the total. Therefore, the correct answer is 2.5mL of bleach.

To make an 80mL, 1 to 8 dilution of bleach solution, you need to mix 10mL of bleach with 70mL of water. This is because a 1 to 8 dilution means that for every 1 part of bleach, you need to add 8 parts of water. So, if you have 10mL of bleach, you would need 80mL in total, with 70mL being water. Therefore, the correct answer is 10mL.

When a 9% bleach solution is diluted to 3 times its original volume, it becomes 1/3 as concentrated. This means that the concentration of bleach has been reduced by a factor of 1/3. Therefore, the new concentration of bleach is 3% (9% * 1/3 = 3%).

To make a 1:10 dilution of bleach solution, you need to mix 1 part of bleach with 9 parts of water. Since the final volume is 200mL, 1 part of bleach would be equal to 200mL/10 = 20mL. Therefore, 20mL of bleach is needed to make a 200mL, 1:10 dilution of bleach solution.

To make a 1:8 dilution of bleach solution, you need to mix 1 part of bleach with 7 parts of water. Since the total volume of the solution is 80mL, 1 part of bleach would be equal to 80mL/8 = 10mL. Therefore, you would need 10mL of bleach to make a 80mL, 1:8 dilution of bleach solution.

When a 20% alcohol solution is diluted to two times its volume, the resulting solution becomes 1/2 as concentrated. This means that the concentration of the solution is halved. Since the original concentration was 20%, halving it gives us a new concentration of 10%. Therefore, the new concentration of the solution is 10%.

To make a 10% bleach solution with a volume of 50mL, 5mL of bleach is needed. This can be calculated by taking 10% of the total volume, which is 50mL, resulting in 5mL.

To make a 20% alcohol solution, we need to mix a 40% alcohol solution with a lower concentration. Since the 40% alcohol solution has twice the concentration of the desired solution, we only need half the volume. Therefore, 2L of the 40% alcohol solution is required to make a 20% alcohol solution.

The procedure calls for 8% acetic acid and requires 1L of it. To calculate the amount of acetic acid needed, we multiply the volume (1L) by the concentration (8%). This gives us 1L * 0.08 = 0.08L or 80mL of acetic acid needed.

To make a 40% alcohol solution, we need to mix a certain amount of 80% alcohol with a certain amount of 0% alcohol. Since the final volume is not specified, we can assume it to be 8L. Let's say we need x liters of 80% alcohol. The amount of 0% alcohol needed would be (8-x) liters. Now, we can set up the equation: 0.8x + 0(8-x) = 0.4(8). Simplifying this equation gives us 0.8x = 3.2. Dividing both sides by 0.8, we find that x = 4. Therefore, we need 4L of 80% alcohol to make a 40% alcohol solution.

When 1mL of serum is diluted to a total volume of 50mL, the dilution factor can be calculated by dividing the final volume (50mL) by the initial volume (1mL). Therefore, the dilution factor is 50. This means that the serum has been diluted 50 times. The dilution factor is expressed as a fraction, where the denominator represents the final volume and the numerator represents the initial volume. Hence, the correct answer is 1/50.

To set up an equation for how much bleach is needed to make a 5% solution for any given volume, we need to multiply the total volume by 5/100. This is because 5% is equivalent to 5/100. By multiplying the total volume by 5/100, we can determine the amount of bleach needed to make a 5% solution.

OF MEANS MULTIPLY

W MEANS WEIGHT OFSOLUTES, V MEANS VOLUME OF TOTAL SOLUTION

To make a 100 gallon lemonade with a concentration that is 1/4 of the original concentration, you would need 25 gallons of the concentrate. This is because if the original concentration is 1 gallon, then 1/4 of that would be 1/4 gallon. Since we need 100 gallons, we would multiply 1/4 gallon by 100, which equals 25 gallons.

A 7:10 dilution of serum can be prepared by mixing seven parts of serum with three parts of saline. This means that for every 7 units of serum, 3 units of saline should be added. This dilution ratio ensures that the concentration of the serum is reduced by a factor of 7/10, making it more suitable for certain laboratory tests or procedures that require a lower concentration.

To make a 1000mL bleach solution with 3 parts bleach and 7 parts water, we need to find the amount of bleach required. Since the solution consists of 10 parts in total, each part is equal to 1000mL/10 = 100mL. Therefore, 3 parts bleach would be equal to 3 * 100mL = 300mL. Hence, 300mL of bleach is needed to make the solution.

To prepare a 1:20, 1000mL dilution of bleach from its concentrate, 50mL of the bleach concentrate is needed. This is because a 1:20 dilution means that for every 1 part of bleach concentrate, 20 parts of water are added. So, to make a 1000mL dilution, 1000/20 = 50mL of bleach concentrate is required.

OF MEANS MULTIPLY

W MEANS WEIGHT OF TABLE SALT, V MEANS VOLUME OF TOTAL SOLUTION

To make a 400mL bleach solution with 1 part bleach and 3 parts water, we need to determine the amount of bleach needed. Since the solution consists of 1 part bleach and 3 parts water, the total number of parts is 1+3=4. To find the amount of bleach, we divide the total volume of the solution (400mL) by the total number of parts (4) and multiply it by the number of parts of bleach (1). Therefore, the amount of bleach needed is (400mL/4) * 1 = 100mL.

A 5:9 dilution of serum can be prepared by mixing five parts of serum with four parts of saline. This means that for every five units of serum, four units of saline are added, resulting in a total volume of nine units. This dilution ratio ensures that the concentration of the serum is reduced while still maintaining a certain proportion of the original serum.

The dilution is the ratio of the volume of the original solution to the final volume after dilution. In this case, 2mL of serum is diluted to a total volume of 13mL. Therefore, the dilution is 2/13, which means that the original serum is diluted by a factor of 2/13.

After spinning down the whole blood and removing the plasma, the red thick fluid remaining contains about 86% red blood cells. When one drop of this packed red blood cells is mixed with 19 drops of saline, the total volume becomes 20 drops. Since the answer is still in percentage, we can calculate the new percentage of red blood cells by dividing the number of drops of red blood cells by the total number of drops and multiplying by 100. Therefore, the new percentage of red blood cells is (1/20) x 100 = 5%. However, since we are instructed not to divide anything by 100, the answer is 5/100 = 0.05 = 4.3%.

To make a 50mL bleach solution with one part bleach and four parts water, you need to mix 10mL of bleach with 40mL of water. This is because one part bleach is equal to 10mL and four parts water is equal to 40mL. Therefore, the correct answer is 10mL.

When one drop of whole blood is mixed with 9 drops of saline, the total volume becomes 10 drops. Since the original whole blood contains 45% red blood cells, this means that 45% of the total volume is made up of red blood cells.

When the blood is mixed with saline, the volume of red blood cells remains the same, but the total volume increases. Therefore, the new percentage of red blood cells in the mixture will be the same as the original percentage, which is 4.5%.

When 1mL of serum is diluted to a total volume of 55mL, the dilution factor can be calculated by dividing the final volume (55mL) by the initial volume (1mL). Therefore, the dilution is 1/55.

To prepare a 5% solution of bleach, we need to mix bleach concentrate with water. The percentage represents the amount of solute (bleach) in the solution. So, for a 5% solution, we need 5mL of bleach in every 100mL of solution. Since we want to prepare a 2L solution, we need to calculate the amount of bleach concentrate needed. 2L is equivalent to 2000mL. Therefore, we need 5mL of bleach for every 100mL of solution. So, for 2000mL of solution, we need 100mL of bleach concentrate.

To prepare a 5% alcohol solution, we need to mix a certain amount of a 40% alcohol solution with water. In this case, the question asks for how much of the 40% alcohol solution is needed. To find this, we can set up a proportion using the concentrations of the two solutions. Let x represent the amount of the 40% alcohol solution needed. The proportion would be (40/100) / (5/100) = x / 2000. Solving for x, we get x = (40/100) * (2000/5) = 250 mL. Therefore, 250 mL of the 40% alcohol solution is needed.

A 1 to 45 dilution of blood can be prepared by mixing one part of blood with 44 parts of saline. This means that for every unit of blood, 44 units of saline are added. This dilution ratio allows for a more accurate and precise measurement of the blood sample, as it reduces the concentration of the blood and makes it easier to work with in laboratory settings.

The dilution is 1/9 because 1 mL of blood is mixed with 8 mL of saline, resulting in a total volume of 9 mL. Therefore, the blood is 1/9 of the total mixture.

To prepare a 16% solution of bleach, 32mL of the bleach concentrate is needed. This is because the concentration of the bleach is given as a percentage, and the total volume of the solution is 200mL. Therefore, to find the amount of bleach concentrate needed, we can calculate 16% of 200mL, which is 0.16 * 200 = 32mL.

To prepare a 2000mL, 5M hydrochloric acid solution, we need to use a 10M hydrochloric acid solution. The concentration of the 10M solution is higher than the desired 5M concentration, so we need to dilute it. The dilution formula is C1V1 = C2V2, where C1 and V1 are the initial concentration and volume, and C2 and V2 are the final concentration and volume. Plugging in the values, we have (10M)(V1) = (5M)(2000mL). Solving for V1, we get V1 = (5M)(2000mL)/(10M) = 1000mL. Therefore, we need to use 1000mL of the 10M hydrochloric acid solution to prepare the desired 2000mL, 5M solution.

To prepare a 5% alcohol solution, we need to mix a certain amount of a 50% alcohol solution with a certain amount of a 0% alcohol solution. Let's assume that x mL of the 50% alcohol solution is used. Since the 50% alcohol solution is twice as concentrated as the desired 5% alcohol solution, we can set up the equation 50% * x mL = 5% * 200 mL. Solving for x, we find that x = 20 mL. Therefore, 20 mL of the 50% alcohol solution is used to prepare the 200 mL, 5% alcohol solution.

To make a 1:25 dilution of bleach solution, you need to mix 1 part bleach with 24 parts water. This means that for every 1 mL of bleach, you need 24 mL of water. Since the desired total volume is 200 mL, you can calculate the amount of bleach needed by dividing 200 mL by 25 (1 part bleach + 24 parts water), which gives 8 mL. Therefore, 8 mL of bleach is needed to make a 200 mL, 1:25 dilution of bleach solution.

W MEANS WEIGHT OF TABLE SALT, V MEANS VOLUME OF TOTAL SOLUTION

The given question asks for the dilution when 2mL of serum is placed in 43mL of saline. To calculate the dilution, we divide the volume of the serum (2mL) by the total volume of the mixture (2mL + 43mL = 45mL). Therefore, the dilution is 2/45.

To make a 4:15 dilution of bleach solution, we need to mix 4 parts of bleach with 15 parts of water. Since the total volume of the diluted solution is 300mL, we can calculate the amount of bleach needed by dividing the total volume by the sum of the parts in the ratio (4 + 15 = 19). Therefore, the amount of bleach needed is (4/19) * 300mL = 63.16mL. However, since the options provided are not exact, the closest option is 80mL.

The dilution is 1/5 because the blood is mixed with 8 mL of saline, resulting in a total volume of 10 mL. The blood volume is 2 mL, so the ratio of blood to total volume is 2/10, which simplifies to 1/5.

To prepare a 200mL solution of bleach, the ratio of bleach to water is 1:39. This means that for every 1 part of bleach, 39 parts of water are needed. Therefore, to find out how much bleach concentrate is needed, we can set up a proportion: 1 part bleach / 39 parts water = x mL bleach / 200 mL solution. Cross-multiplying and solving for x, we find that x = (1/39) * 200 = 5 mL. Therefore, 5 mL of the bleach concentrate is needed to prepare the 200mL solution.