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pychu [463]
3 years ago
15

In an experiment, hydrochloric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate was form

ed during the reaction. A cross drawn at the base of each flask became gradually invisible due the formation of this yellow precipitate. The time taken for the cross to become invisible was recorded. A partial record of the experiment is shown.
Experimental Record Flask Volume of

HCl Volume of

Sodium Thiosulfate Volume of

Water Time

1 10 mL 10 mL 40 mL 14 seconds

2 10 mL 20 mL 30 mL

3 10 mL 30 mL 20 mL

4 10 mL 40 mL 10 mL


Based on your knowledge of factors that affect the rates of chemical reactions, predict the trend in the last column of the experimental record. Use complete sentences to explain the trend you predicted. You do not have to determine exact values for time; just describe the trend you would expect (increase or decrease) and why it occurs
Chemistry
1 answer:
morpeh [17]3 years ago
5 0

Answer:

The time taken for the cross to become invisible decreases.

Explanation:

We know that one of the factors affecting the rate of reaction is the concentration of reactants. From the collision theory, we know that the higher the concentration of reactants, the greater the possibility of effective collision between reactants leading ultimately to an increase in the rate of reaction. Increase in the rate of reaction implies that the reaction takes a shorter time to reach completion.

In the case of the reaction shown in the question, the point when the reaction is completed is observed by the time take for the cross mark to become invisible. If we look at the given data closely, we will notice that the volume of acid was held constant, the volume of thiosulphate was increased gradually while the volume of water was decreased accordingly. This implies that the concentration of the reactants was increased. Decreasing the volume of water increases reactant concentration.

As explained above, increase in reactant concentration increases the rate of reaction. Hence, the rate of reaction of the acid and thiosulphate increases as reactant concentration increases and the cross mark becomes invisible faster. This implies that in the last column for time taken for the cross to become invisible, the values of time decreases steadily as concentration of reactants increases.

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The number of moles of solute in 200.ml of a 0.500 m solution is
IrinaK [193]

Answer:

I believe the answer is 0.100.

Explanation:

Hope my answer has helped you!

8 0
3 years ago
Temperature is ____ related to the average kinetic energy of a gas.
Nastasia [14]

Answer:

directly

Explanation:

Temperature is defined as the average kinetic energy per particle of a gas, hence temperature and average kinetic energy are directly related meaning that if kinetic energy of a gas increases temperature will also increase.

5 0
3 years ago
Read 2 more answers
In the lab you measure a clean dry crucible and cover to be 24.36 grams. You obtain a 2cm piece of pure magnesium metal. After s
mart [117]

Answer:

1) 0.3g Mg

2)0.5g MgO

3)0.2g O

4)0.01mol Mg & 0.01mol O

5)0.01mol MgO

6) Empirical formula MgO

Explanation:

The mass og Mg is obtained by substracting 24.36g from 24.66g:

24.66 - 24.36 = 0.3g Mg

The ignition of Mg means that it's reacting with oxygen to form an oxide. The increase in the crucible mass after the Mg ignition is due to the addition of oxygen. However, the addition of few drops of water produces a new compound: a hydroxide. According to the oxidation state og Mg (2+), the only magnesium oxide possible is MgO. It happens because the oxidation state of oxygen in oxides is 2-. Which means that just one oxygen atom is required to electrically neutralize one magnesium atom.

We can use a conversion factor to know how much MgO is made from from 0.3 g of Mg:

0.3g Mg*\frac{16gO}{24.3gMg}= 0.2g O

Thereby the mass of the oxide is 0.2g O + 0.3g Mg = 0.5g MgO

We convert the mass of oxygen and magnesium to the respective amounts in moles by using conversion factors:

0.2g O*\frac{1 mol O}{16g O}= 0.01mol O

0.3g Mg*\frac{1mol Mg}{24.3g Mg}= 0.01mol Mg

The moles of MgO can be obtained from:

0.5g MgO*\frac{1mol MgO}{40.3g MgO}= 0.01mol MgO

To obtain the empirical formula, the amount fo moles of each elements must be divided by the smallest one, in this case, 0.01.

The result for both number of  Mg atoms and O atoms is 1. This can be interpreted to mean that there is a Mg atom for each O atom forming the  formula unit of the compound.

The step when water is added to the compound resulting after heating does not affect the calculations necessary for the magnesium oxide.

4 0
3 years ago
Pls help me over here
alexgriva [62]

Answer:

1 and the element is hydrogen (there is an exception for the octet rule for the element hydrogen) hope this helps

Explanation:

8 0
2 years ago
Water softeners often replace calcium ions in hard water with sodium ions. since sodium compounds are soluble, the presence of s
Mamont248 [21]
% mass Na = (g Na / g H2O) x 100 
<span>g Na = (% mass Na)(g H2O) / 100 = (5.2 x 10^-4 g Na / g H2O) </span>

<span>2.4 g Na x (1 g H2O / 5.2 x 10^-4 g Na) = 4600 g Na </span>

<span>4600 g Na x (1 mL H2O / 1 g H2O) = 4600 mL H2O = 4.6 L H2O which is a little more than a gallon</span>
6 0
3 years ago
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