What is the role of starch in the titration reaction?

A motorist discovers that her auto tire measures 29.2 psi rather than the recommended 35 psi. If the tire’s volume is assumed co

I am Lyosha [343]

Answer:

0.20 moles

Explanation:

The pressure is proportional to the quantity of gas at a given temperature and volume. So, the quantity needs to be increased by a factor of ...

(35 psi)/(29.2 psi) = 175/146 ≈ 1.19863

The fractional increase required is ...

1.19863 -1 = 0.19863

__

The quantity of air currently in the tire is ...

1 mol·519.67°R/(atm·23.6442 L) × (29.2/14.7 atm) × (11.6 L) / (45+459.67)°R

= 1.0035 mol

so we need to add ...

(fraction to add) × (current quantity) = amount to add

0.19863 × 1.0035 mol = 0.1993 mol = amount to add

About 0.20 moles of air must be added to the tire to bring the pressure up.

5 0

3 years ago

3. At 35 C, a sample of gas has a volume of 256 ml and a pressure of 720.torr. What would the volume

STatiana [176]

Answer:

The volume will be 185.83 mL.

Explanation:

Gay-Lussac's law indicates that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. Gay-Lussac's law can be expressed mathematically as follows:

$\frac{P}{T} =k$

Where P = pressure, T = temperature, k = Constant

Boyle's law says that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. Boyle's law is expressed mathematically as:

P*V=k

Where P = pressure, V = volume, k = Constant

Finally, Charles's Law consists of the relationship that exists between the volume and the temperature of a certain quantity of ideal gas, which is kept at a constant pressure. For a given sum of gas at a constant pressure, as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases because the temperature is directly related to the energy of the movement of the gas molecules. .

In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:

$\frac{V}{T} =k$

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

$\frac{P*V}{T} =k$

Studying two different states, an initial state 1 and a final state 2, it is satisfied:

$\frac{P1*V1}{T1} =\frac{P2*V2}{T2}$

In this case:

P1= 720 torr
V1= 256 mL
T1= 35 C= 308 K (being 0 C= 273 K)
P2= 1.25 atm= 950 torr (being 1 atm= 760 torr)
V2= ?
T2= 22 C= 295 K

Replacing:

$\frac{720 torr*256 mL}{308 K} =\frac{950 torr*V2}{295 K}$

Solving:

$V2= \frac{295K}{950 torr} *\frac{720 torr*256 mL}{308 K}$

V2= 185.83 mL

<u><em>The volume will be 185.83 mL.</em></u>

6 0

3 years ago

Measurements show that enthalpy of a mixture of gaseous reactants decreases by 228. kJ during a certain chemical reaction, which

Tcecarenko [31]

Total change in energy = Heat produced by system + work done on the system
= 228 - 55
= 173 kJ

Because this energy is released as heat, the reaction is exothermic.

7 0

3 years ago

Read 2 more answers

Cu + 2AgNO3 → Cu(NO3)2 + 2Ag

Eva8 [605]

Answer:

$m_{Ag}=135.8gAg$

$Y=88.4\%$

Explanation:

Hello there!

In this case, according to the described chemical reaction, it is possible to compute the theoretical mass of silver as mass via the 1:2 mole ratio of copper to silver and their atomic mass in the periodic table, in order to perform the following stoichiometric setup:

$m_{Ag}=40.gCu*\frac{1molCu}{63.55gCu}*\frac{2molAg}{1molCu}*\frac{107.87gAg}{1molAg}\\\\ m_{Ag}=135.8gAg$

Next, given the actual yield of 120 g, we compute the percent yield via:

$Y=\frac{120g}{135.8g}*100\%\\\\Y=88.4\%$

Regards!

4 0

3 years ago

Would aluminum be as useful as food wrapping if it had a much lower melting point? Explain your answer.

Salsk061 [2.6K]

The correct answers are as follows:

1. Aluminium will not be useful as food wrapping if it has a much lower melting point.

Aluminum is a metallic element that is malleable and soft, thus, it is easy to beat it into thin sheet, which are used to package food. The thin sheet is called aluminium foil. Aluminum is useful as a food wrapping because it has high temperature and thus, it does not react with food (the hotness of the packaged food is not capable of melting the metal). If the melting point of aluminium is lower, this implies that little temperature, such as the one from hot food will be able to melt aluminum foil, thus allowing the food to be contaminated with the metal.

2. When bleach react with fabric dye chemical change occur in the fabric.

The major element in bleach is chlorine. When laundry bleach is added to a fabric, the chlorine component of the bleach will react with the fabric dye and cause a colour change in the fabric. This type of change is called chemical change, because the original colour of the fabric can not be recovered.

3. Every substance has specific properties, which can be used to identify it. Two of such specific properties are melting point and boiling point. Melting point refers to a specific temperature at which a solid substance will melt while boiling point refers to a specific temperature at which a liquid substance will boil and turn to steam.

Water for instance has a boiling point of 100 degree Celsius. To find out if an unknown substance is water, one can determine the boiling point of such liquid. A boiling point of 100 degree Celsius will strongly signify that the substance is probably water. The same thing applies to melting point. If the specific boiling and melting point of substances are known, then they can be used to identify them.

4 0

3 years ago