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3 years ago

Which statement describes a convex lens?

2 answers:

7 0

A convex lens will C. It bends light rays inward. A convex lens will take the light and bend it inward towards a focal point.

Hope I helped!

Umnica [9.8K]3 years ago

4 0

C is the answer :) Plz Give brainliest and Rate

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A 0.63 mole sample of CO2 is in a 750 mL container. What is the pressure of the gas in torr when the has is held at -35.6oC?

kipiarov [429]

Answer:

12426torr

Explanation:

The following data were obtained from the question:

n = 0.63 mole

V = 750mL = 750/1000 = 0.75L

T = -35.6°C = -35.6 + 273 = 237.4K

R =0.082atm.L/Kmol

P =?

Using the ideal gas equation PV = nRT, the pressure can be obtained as follows:

PV = nRT

P = nRT/V

P = (0.63 x 0.082 x 237.4)/0.75

P = 16.35atm

Now let us convert this pressure (i.e 16.35atm) to a pressure in torr. This is illustrated below:

1atm = 760torr

16.35atm = 16.35 x 760 = 12426torr

Therefore, the pressure of the gas is 12426torr

4 0

3 years ago

Read 2 more answers

A student conducts an experiment to see how music affects plant growth. The student obtains four identical plants. Each one is p

frez [133]

Answer:

A. A line graph

Explanation:

You use line graphs to track changes over time. Line graphs are better when the changes are small. They are also more useful when you want to compare changes over the same period for more than one group, for example, plants exposed to music and a control group.

B is wrong. A pie chart is best for comparing parts of a whole.

C is wrong. You can use a bar graph to track changes over time, but small changes are harder to spot.

D is wrong. You use a timeline to mark important points in time, for example, when you are deciding the times when you must complete various stages of a project.

Which of the charts below do you think is more helpful in showing the change in plant height over time?

7 0

4 years ago

Choose the aqueous solution that has the highest boiling point. These are all solutions of nonvolatile solutes and you should as

FrozenT [24]

Answer:

0.100 M AlCl₃

Explanation:

The variation of boiling point by the addition of a nonvolatile solute is called ebullioscopy, and the temperature variation is calculated by:

ΔT = W.i

Where W = nsolute/msolvent, and i is the Van't Hoff factor. Because all the substances have the same molarity, n is equal for all of them.

i = final particles/initial particles

C₆H₁₂O₆ don't dissociate, so final particles = initial particles => i = 1;

AlCl₃ dissociates at Al⁺³ and 3Cl⁻, so has 4 final particles and 1 initial particle, i = 4/1 = 4;

NaCl dissociates at Na⁺ and Cl⁻ so has 2 final particles and 1 initial particle, i = 2/1 = 2;

MgCl₂ dissociates at Mg⁺² and 2Cl⁻, so has 3 final particles and 1 initial particle, i = 3/1 = 3.

So, the solution with AlCl₃ will have the highest ΔT, and because of that the highest boiling point.

8 0

3 years ago

PLEASE HELP FAST IM ABOUT TO FAIL PLEASE HELP PLEASE HELP FAST HELP HELP THIS IS DESPRATE

MariettaO [177]

1. 0.240 liters of water would be needed to dissolve 21.6 g of lithium nitrate to make a 1.3 M (molar) solution.

2. 2.9 M is the molarity of a solution made of 215.1 g of HCl is dissolved to make 2.0 L of solution.

3.83.3 ml of concentrated 18 M H2SO4 is needed to prepare 250.0 mL of a 6.0 M solution.

4. 135 ml of stock HBr will be required to dilute the solution.

5. 150 ml of water should be added to 50.0 mL of 12 M hydrochloric acid to make a 4.0 M solution

6. The pH of the resulting solution is 13.89

Explanation:

The formula used in solving the problems is

number of moles= $\frac{mass}{atomic mass of one mole}$ 1st equation

molarity = $\frac{number of moles}{volume}$ 2nd equation

Dilution formula

M1V1 = M2V2 3rd equation

1. Data given

mass of Lithium nitrate = 21.6 grams

atomic mass of on emole lithium nitrate = 68.946 gram/mole

Molarity is given as 1.3 M

VOLUME=?

Calculate the number of moles using equation 1

n = $\frac{21.6}{68.946}$

= 0.313 moles of lithium nitrate.

volume is calculated by applying equation 2.

volume = $\frac{0.313}{1.3}$

= 0.240 litres of water will be used.

2. Data given:

mass of HCl = 215.1 gram

atomic mass of HCl = 36.46 gram/mole

volume = 2 litres

molarity = ?

using equation 1 number of moles calculated

number of moles = $\frac{215.1}{36.46}$

number of moles of HCl = 5.899 moles

molarity is calculated by using equation 2

M = $\frac{5.899}{2}$

= 2.9 M is the molarity of the solution of 2 litre HCl.

3. data given:

molarity of H2SO4 = 18 M

Solution to be made 250 ml of 6 M

USING EQUATION 3

18 x V1= 250 x 6

V1 = 83.3 ml of concentrated 18 M H2SO4 will be required.

4. data given:

M1= 10M, V1 =?, M2= 3 ,V2= 450 ml

applying the equation 3

10 x VI = 3x 450

V1 = 135 ml of stock HBr will be required.

5. Data given:

V1 = 50 ml

M1= 12 M

V2=?

M2= 4

applying the equation 3

50 x 12 = 4 x v2

V2 = 150 ml.

6. data given:

HCl + NaOH ⇒ NaCl + H20

molarity of NaOH = 0.525 M

volume of NaOH = 25 ml

molarity of acid HCl= 75 ml

volume of HCl = 0.335 ml

pH=?

Number of moles of NaOH and HCl is calculated by using equation 1 and converting volume in litres

moles of NaOH = 0.0131

moles of HCl= 0.025 moles

The ratio of moles is 1:1 . To find the unreacted moles of acid and base which does not participated in neutralization so the difference of number of moles of acid minus number of moles of base is taken.

difference of moles = 0.0119 moles ( NaOH moles is more)

Molarity can be calculated by using equation 1 in (25 +75 ml) litre of solution

molarity = $\frac{0.0119}{0.1}$

= 0.11 M (pOH Concentration)

14 = pH + pOH

pH = 14 - 0.11

pH = 13.89

3 0

3 years ago

Some headache medicines are fine powders that are dissolved in water and then ingested. These medicines claim they work faster t

ryzh [129]

i mean it can be true and it cant at the same time. i mean medicine doesn't always work on a person. but it is said that medicine that is in powder form is more efficient.

but i believe its D or A

6 0

3 years ago

Read 2 more answers