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3 years ago

A 12 gram piece of Cu at 475 oC is placed in contact with a 15 gram piece of Cr at 265 oC.

Chemistry

1 answer:

ale4655 [162]3 years ago

4 0

Answer:

349.22°C

Explanation:

Let the final temperature of the two pieces of metal be x.

Now, the warmer metal which is C u reduces from 475°C to x. Thus Δt for C u is; Δt1 = 475 - x.

The cooler metal Cr increases in temperature from 265°C to x. Thus, it's change in temperature is Δt for Cr is; Δt2 = x - 265.

Now from conservation of energy, the amount of energy leaving the C u metal is equal to the amount of energy entering the Cr metal.

Thus;

q_lost = q_gain

Where;

q_lost = m1•c1•Δt1

q_gained = m2•c2•Δt2

Now, c1 & c2 are the specific heat capacity of C u and Cr respectively.

From online tables, c1 = 0.385 J/g°C and c2 = 0.46 J/g°C

We are given;

m1 = 12g and m2 = 15g

Thus;

12 × 0.385 × (475 - x) = 15 × 0.46 × (x - 265)

2194.5 - 4.62x = 6.9x - 1828.5

6.9x + 4.62x = 2194.5 + 1828.5

11.52x = 4023

x = 4023/11.52

x = 349.22°C

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) determine the theoretical yield and the percent yield if 21.8 g of k2co3 is produced from reacting 27.9 g ko2 with 29.0 l of c

Airida [17]

The Balanced Chemical Equation is as follow;

4 KO₂ + 2 CO₂   → 2 K₂CO₃ + 3 O₂

First find out the Limiting Reagent,
According to equation,

284 g (4 moles) KO₂ reacted with = 44.8 L (2 moles) of CO₂
So,
  27.9 g of KO₂ will react with = X L of CO₂

Solving for X,
X = (44.8 L × 27.9 g) ÷ 284 g

X =  4.40 L of CO₂

Hence, to consume 27.9 g of KO₂ only 4.40 L CO₂ is required, while, we are provided with 29 L of CO₂, it means CO₂ is in excess and KO₂ is is limited amount, Therefore, KO₂ will control the yield of K₂CO₃. So,

According to eq.

284 g (4 moles) KO₂ formed = 138.2 g of K₂CO₃
So,
27.9 g of KO₂ will form = X g of K₂CO₃

Solving for X,
X = (138.2 g × 27.9 g) ÷ 284 g

X =  13.57 g of K₂CO₃

So, 13.57 g of K₂CO₃ formed is the theoretical yield.

%age Yield = 13.57 / 21.8 × 100

%age Yield = 62.24 %

3 0

3 years ago

Read 2 more answers

Use the following equation to answer the questions below:

Gala2k [10]

Explanation:

The equation of the reaction is given as;

Be + 2HCl → BeCl2 + H2

What is the mass of beryllium required to produce 25.0g of beryllium chloride?

1 mol of Be produces 1 mol of BeCl2

Converting to mass;

Mass = Molar mass * Number of moles

9.01g of Be produces 79.92g of BeCl2

xg of Be produces 25g of BeCl2

Solving for x;

x = 25 * 9.01 / 79.92

x = 2.82 g

What is the mass of hydrochloric acid required to produce 25.0g of beryllium chloride? g

Converting 25.0g of beryllium chloride to moles;

Number of moles = Mass / Molar mass

Number of moles = 25 / 79.92 = 0.3128 mol

2 mol of HCl produces 1 mol of BeCl2

x mol of HCl would produce 0.3128 mol of BeCl2

solving for x;

x = 0.3128 * 2 = 0.6256 mol

Converting to mass;

Mass = 0.6256 * 36.5 = 22.83 g

What is the mass of hydrogen gas produced when 25.0g of beryllium chloride is also produced? g

25g of BeCl2 = 0.3128 mol of BeCl2

From the equation;

1 mol of H2 is produced alongside 1 mol of BeCl2

This means;

0.3128 mol of H2 would also be produced alongside 0.3128 mol of BeCl2

Mass = Number of moles * Molar mass

Mass = 0.3128mol * 2.0159 g/mol = 0.6306 g

3 0

3 years ago

"Calculate the number of millimoles in 500 mg of each of the following amino acids: alanine (MW = 89), leucine (131), tryptophan

Cloud [144]

Answer:

- Alanine = 5.61 mmoles

- Leucine = 3.81 mmoles

- Tryptophan = 2.45 mmoles

- Cysteine = 4.13 mmoles

- Glutamic acid = 3.40 mmoles

Explanation:

Mass / Molar mass = Moles

Milimoles = Mol . 1000

500 mg / 1000 = 0.5 g

- Alanine = 0.5 g / 89 g/m → 5.61x10⁻³ moles . 1000 = 5.61mmoles

- Leucine = 0.5 g / 131 g/m → 3.81 x10⁻³ moles . 1000 = 3.81 mmoles

- Tryptophan = 0.5 g / 204 g/m → 2.45x10⁻³ moles . 1000 = 2.45 mmoles

- Cysteine = 0.5 g / 121 g/m → 4.13x10⁻³ moles . 1000 = 4.13 mmoles

- Glutamic acid = 0.5 g 147 g/m → 3.40x10⁻³ moles . 1000 = 3.4 mmoles

5 0

3 years ago

What volume of 0.100 M HCl will react completely with 50.00 mL of 0.200 M NaOH?

skelet666 [1.2K]

Equation of reaction
Hcl+NaoH-->Nacl+H2O
1:1
Using the formula CaVa/CbVb=na/nb
Ca(Concentation of acid)= 0.100M
Cb(Concentration of base)=0.200M
Va=?
VB=50.00ml
na=1
nb=1
from the formula
Va= CbVbna/Canb
Va= 0.2*50*1/0.1*1
=10/0.1=100ml
Therefore volume of acid = 100ml

7 0

3 years ago

Lowering an object decrease is potential

Tresset [83]

Answer:

Lowering the object near the ground decreases its potential energy.

Explanation:

Potential Energy : Energy possessed by the object due to its shape ,Size and Position is called potential energy.

Example :

Change in shape and size : When you compress the spring , potential energy is introduced in it . So it expand quickly when you remove your hand.

Change in position : when you swing , after attaining maximum height (extreme ends) , the swing comes back on its on .This is because at maximum height ,the swing has maximum Potential energy . Hence it fall back on its on because it already has potential energy.

Potential energy(P) is given by the formula :

P = mgh

where ,

m= mass of the object

g = acceleration due to gravity

h = height of the object from the ground

If the height of the object increases from the ground , its potential energy also get increase.

On lowering the object The height of the object from the ground reduces . So potential energy also reduces.

8 0

3 years ago