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Ierofanga [76]
3 years ago
15

What is the molality of a solution made by dissolving 137.9g of sucrose in 414.1g of water?

Chemistry
1 answer:
Daniel [21]3 years ago
8 0

Answer: 2.71 moles of solute for every 1 kg of solvent.

Explanation: As you know, the molality of a solution tells you the number of moles of solute present for every 1 kg of the solvent.This means that the first thing that you need to do here is to figure out how many grams of water are present in your sample. To do that, use the density of water.500.mL⋅1.00 g1mL=500. g Next, use the molar mass of the solute to determine how many moles are present in the sample.115g⋅1 mole NanO385.0g=1.353 moles NaNO3So, you know that this solution will contain 1.353moles of sodium nitrate, the solute, for 500. g of water, the solvent.In order to find the molality of the solution, you must figure out how many moles of solute would be present for 1 kg=103g of water.103g water⋅1.353 moles NaNO3500.g water=2.706 moles NaNO3You can thus say that the molality of the solution is equal to molality=2.706 mol kg−1≈2.71 mol kg−1 The answer is rounded to three sig figs.

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Put the following metric units in order from largest to smallest pL, mL, dL, kL
earnstyle [38]

Answer:

kL, dL, mL, pL

Explanation:

pL stands for picoliters. This is equal to 1 × 10⁻¹² (0.000000000001) liters.

mL stands for milliliters. This is equal to 1 × 10⁻³ (0.001) liters.

dL stands for deciliters. This is equal to 1 × 10⁻¹ (0.1) liters.

kL stands for kiloliters. This is equal to 1 × 10³ (1000) liters.

8 0
3 years ago
When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II)
katen-ka-za [31]

Answer:

3.81 g Pb

Explanation:

When a lead acid car battery is recharged, the following half-reactions take place:

Cathode: PbSO₄(s) + H⁺ (aq) + 2e⁻ → Pb(s) + HSO₄⁻(aq)  

Anode: PbSO₄(s) + 2 H₂O(l) → PbO₂(s) + HSO₄⁻(aq) + 3H⁺ (aq) + 2e⁻

We can establish the following relations:

  • 1 A = 1 c/s
  • 1 mole of Pb(s) is deposited when 2 moles of e⁻ circulate.
  • The molar mass of Pb is 207.2 g/mol
  • 1 mol of e⁻ has a charge of 96468 c (Faraday's constant)

Suppose a current of 96.0A is fed into a car battery for 37.0 seconds. The mass of lead deposited is:

37.0s.\frac{96.0c}{s} .\frac{1mole^{-} }{96468c} .\frac{1molPb}{2mole^{-} } .\frac{207.2gPb}{1molPb} =3.81gPb

6 0
3 years ago
What is a characteristic that can be observed or measured without changing the chemical makeup of a substance? *
olga55 [171]
The correct answer is B
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A compound that is composed of only carbon and hydrogen contains 85.7% c and 14.3% h by mass. what is the empirical formula of t
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The empirical formula is CH2
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2 years ago
3. Some of the reagents used in this lab are easily confused: such as persulfate (S208?)
padilas [110]

Answer:

Different compounds are formed.

Explanation:

Due to this switching of chemicals, the result of both beakers will be different because the chemicals react with the different solution in the beaker. The composition of both chemicals are different from one another which produces different compounds or products when they are mixed with the solution so we can say that this switching of chemicals will definitely affect the results of the experiment. The student will observe the formation of different compounds and different colour of the solution.

3 0
3 years ago
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