Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points

Suppose an ice cube weighing 36.0 g at a temperature of 10°C is placed in 360 g water at a temperature of 20°C. Calculate the te

Scilla [17]

Answer:

10.44 °C

Explanation:

When the thermal equilibrium is reached, both of the substances have the same final temperature (T). The liquid water will lose heat, and the ice cube will absorb this heat. The temperature of the ice will increase until it reaches 0°C, at this temperature, it will change of phase for liquid, absorbing heat, but without a change in the temperature. Then the temperature will increase until the equilibrium.

By the energy conservation, the total amount of heat must be equal to 0:

Qice + Qmelting + Qliquid1 + Qliquid2 = 0

Liquid 1 is the ice after melting, and liquid 2 the liquid that was already at the flask. When there's a change of temperature:

Q = n*c*ΔT, where n is the number of moles, c is the heat capacity and ΔT is the temperature change (final - initial). The temperature variation in °C is equal in K, so the temperature may be used in °C.

The melting heat is:

Q = n*Hfus, Hfus = 6007 J/mol

The molar mass of the water is 18 g/mol, so the number of moles of the water and the ice are:

nwater = nliquid1 = 360/18 = 20 moles

nice = 36/18 = 2 moles

Qice + Qmelting + Qliquid1 + Qliquid2 = 0

2*38*(0 - (-10)) + 2*6007 + 2*75*(T - 0) + 20*75*(T - 20) = 0

760 + 12014 + 150T + 1500T - 30000 = 0

1650T = 17226

T = 10.44 °C

4 0

3 years ago

Comparison between alkyl nucleophilic substitution with acyl nucleophilic substitution

S_A_V [24]

Answer:

in both nucleophil attach the c and leaving group leave but in acyl nu. subsituation c of carbonyl because of double bond with o have bigger positive charge and is better electrophil so do it faster,also alkyl nu. subsituation can have rearangment if going from sn1 and in sn2 sterichemistry of molecule change , acyl nu. subsituation most of time is better

4 0

3 years ago

Hydrogenation reactions, in which H2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer indu

ddd [48]

<u>Answer:</u> The amount of heat released is 56 MJ.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of $C_2H_6$ = 12 kg = 12000 g (Conversion factor: 1 kg = 1000 g)

Molar mass of $C_2H_6$ = 30 g/mol

Putting values in above equation, we get:

$\text{Moles of }C_2H_6=\frac{12000g}{30g/mol}=400mol$

The chemical reaction for hydrogenation of ethene follows the equation:

$C_2H_4+H_2\rightarrow C_2H_6$

By Stoichiometry of the reaction:

When 1 mole of ethane releases 140 kJ of heat.

So, 400 moles of ethane will release = $\frac{140}{1}\times 400=56000kJ$ of heat.

Converting this into Mega joules, using the conversion factor:

1 MJ = 1000 kJ

So, $\Rightarrow 56000kJ\times (\frac{1MJ}{1000kJ})=56MJ$

Hence, the amount of heat released is 56 MJ.

8 0

3 years ago

If you performed this experiment using mgcl2 as the solute would the molar concentration of mgcl2 that is isotonic to the potato

Mama L [17]

The answer to this question would be: lower molar concentration

Osmotic pressure is influenced by the number of ions and the concentration of the molecule in the solution. In NaCl, the molecule will split into 1 Na+ ion and 1 Cl- ion which results in 2 ions per compound. In MgCl2, the compound will split into 1 Mg2+ ion and 2 Cl- ion which results in 3 ions. Therefore, the osmotic pressure of MgCl2 will be 3/2 times of NaCl.
MgCl2 will need less concentration to achieve same osmotic pressure as NaCl. If the MgCl2 solution is isotonic with NaCl, the concentration of MgCl2 would be lower than NaCl

5 0

4 years ago

A chef is cooking with a 2000-gram stainless steel skillet. Stainless steel has a specific heat capacity of 0.450 J/(g *oC). How

LuckyWell [14K]

Answer:

Q = 90,000 J

Explanation:

Given data:

Mass skillet = 2000 g

Specific heat capacity = 0.450 J/g.°C

Energy required to raise temperature = ?

Initial temperature = 25°C

Final temperature = 125°C

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 125°C - 25°C

ΔT = 100°C

Q = 2000 g × 0.450 J/g.°C × 100°C

Q = 90,000 J

8 0

3 years ago