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3 years ago

What is the relationship between air resistance and surface area?

1 answer:

5 0

Air resistance depends on two important factors - the speed of the object and it's surface area. Increasing the surface area of an object decreases it's speed

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Licemer1 [7]

Answer:

B. Yes, because the mass of all the products of burning is equal to the mass

of the reactants (wood and oxygen gas).

Explanation:

good luck

3 0

3 years ago

The student plans to conduct a spectrophotometric analysis to determine the concentration of Cu2+(aq) in a solution. The solutio

Lelechka [254]

Answer:

The wavelength the student should use is 700 nm.

Explanation:

Attached below you can find the diagram I found for this question elsewhere.

Because the idea is to minimize the interference of the Co⁺²(aq) species, we should <u>choose a wavelength in which its absorbance is minimum</u>.

At 400 nm Co⁺²(aq) shows no absorbance, however neither does Cu⁺²(aq). While at 700 nm Co⁺²(aq) shows no absorbance and Cu⁺²(aq) does.

6 0

3 years ago

To determine the concentration of 20.00 mL of an unknown solution of a monoprotic acid, it is titrated with 0.1093 M sodium hydr

Elanso [62]

Answer:

d) 0.1202 M

Explanation:

Let's consider the neutralization reaction between NaOH and a generic monoprotic acid.

NaOH + HA → NaA + H₂O

The used volume of NaOH is 41.63 mL - 19.63 mL = 22.00 mL. The moles of NaOH are:

22.00 × 10⁻³ L × 0.1093 mol/L = 2.405 × 10⁻³ mol

The molar ratio of NaOH to HA is 1:1. The moles of HA that reacted are 2.405 × 10⁻³ moles.

The molar concentration of HA is:

2.405 × 10⁻³ mol / 20.00 × 10⁻³ L = 0.1202 M

7 0

3 years ago

A 0.500-g sample containing Na2CO3 plus inert matter is analyzed by adding 50.0 mL of 0.100 M HCl, a slight excess, boiling to r

Yakvenalex [24]

The percentage by mass of Na2CO3 in the sample is 48%.

The equation of the reaction of Na2CO3 with HCl;

Na2CO3(aq) + 2HCl(aq) ------> 2NaCl(aq) + H2O(l) + CO2(g)

Since the HCl is in excess, the excess is back titrated with NaOH as follows;

NaOH (aq) + HCl(aq) ---->NaCl(aq) + H2O(l)

Number of moles of HCl added = 0.100 M × 50/1000 L = 0.005 moles

Number of moles of NaOH added = 5.6/1000 × 0.100 M = 0.00056 moles

Since the reaction of NaOH and NaOH is 1:1, 0.00056 moles of HCl reacted with excess HCl.

Amount of HCl that reacted with Na2CO3 = 0.005 moles - 0.00056 moles = 0.0044 moles

Now;

1 mole of Na2CO3 reacts with 2 moles of HCl

x moles of Na2CO3 reacts with 0.0044 moles of HCl

x = 1 mole × 0.0044 moles / 2 moles

x = 0.0022 moles

Mass of Na2CO3 reacted = 0.0022 moles × 106 g/mol = 0.24 g

Percentage of Na2CO3 in the sample = 0.24 g/ 0.500-g × 100/1 = 48%

Learn more about back titration: brainly.com/question/25485091

5 0

2 years ago

Which statement describes a scientific theory?

vichka [17]

Best Answer
C) is the best description, although a scientific theory is not necessarily a "fact". They are, however, based on evidence.

A) is complete garbage.

B) is a good description of a scientific "law"- something that predicts how a certain event will occur without explaining why this is (for instance, the law of gravity accurately describes the gravitational forces between two bodies, but does not explain why these forces are there).

D) is a scientific "hypothesis"- an explanation for an observed phenomena that is yet to be proven.

7 0

3 years ago

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