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4 years ago

A _ _ has a definite composition that will not vary

Chemistry

1 answer:

emmasim [6.3K]4 years ago

7 0

Answer: Mixtures do not have the same composition, properties, and appearance throughout.

Explanation: It does not vary from sample to sample.

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35.2 J of heat is

ruslelena [56]

The specific heat : c = 0.306 J/g K

<h3>Further explanation</h3>

Given

Heat = 35.2 J

Mass = 16 g

Temperature difference : 7.2 K =

Required

The specific heat

Solution

Heat can be calculated using the formula:

Q = mc∆T

Q = heat, J

m = mass, g

c = specific heat, joules / g ° C

∆T = temperature difference, ° C / K

Input the value :

c = Q / m.∆T

c = 35.2 / 16 x 7.2

c = 0.306 J/g K

7 0

3 years ago

Express the rate of the reaction in terms of the change in concentration of each of the reactants and products.

weeeeeb [17]

Answer:

c. rate=−1/2Δ[HBr]/Δt=Δ[H2]/Δt=Δ[Br2]/Δt

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

$2HBr(g)\rightarrow H_2(g)+Br_2(g)$

Thus, the rate is given as:

$rate=-\frac{1}{2} \frac{\Delta [HBr]}{\Delta t}=\frac{\Delta [Br_2]}{\Delta t} =\frac{\Delta [H_2]}{\Delta t}$

It is necessary to remember that each concentration to time interval is divided into the stoichiometric coefficient, that is why HBr has a 1/2. Moreover, the concentration HBr is negative since it is a reactant and it has a negative rate due to its consumption.

Therefore, the answer is:

c. rate=−1/2Δ[HBr]/Δt=Δ[H2]/Δt=Δ[Br2]/Δt

Best regards.

4 0

4 years ago

Which isomer of 1-bromo-4-tert-butylcyclohexane reacts faster when refluxed with potassium tert-butoxide?

grigory [225]

Answer:

See explanation.

Explanation:

Since potassium tert-butoxide is a strong bulky base, we expect that an elimination reaction predominates.

This reaction is expected to occur by E2 mechanism. The cis isomer of 1-bromo-4-tert-butylcyclohexane is known to react faster by E2 mechanism because it fulfills the anticoplanar arrangement required for for E2 mechanism, where the leaving group and adjacent proton must be anti to each other and in the same plane. The trans isomer can not fulfill this requirement.

7 0

3 years ago

2 H2(g) + O2(g) 2 H2000

guajiro [1.7K]

A. 2 x 3 = 6 mol H2O

4 0

3 years ago

A serving of soup contains 5.0 g of fat, 20.0 g of carbohydrates, and 3.0 g of protein. Determine how many kilocalories (kcal) a

marta [7]

Answer: The amount of kilocalories contained in the given serving of soup is 0.137 kCal

Explanation:

As per the USDA:

Carbohydrates provide 4 calories per gram, protein provides 4 calories per gram, and fat provides 9 calories per gram.

We are given

Mass of fat in the soup serving = 5.0 g

Mass of carbohydrates in the soup serving = 20.0 g

Mass of protein in the soup serving = 3.0 g

Conversion factor used: 1 kCal = 1000 Cal

Applying unitary method:

For Fat:

1 gram of fat provides 9 calories

So, 5.0 gram of fat will provide = $\frac{9}{1}\times 5.0=45Cal=0.045kCal$

For Carbohydrates:

1 gram of carbohydrates provides 4 calories

So, 20.0 gram of carbohydrates will provide = $\frac{4}{1}\times 20.0=80Cal=0.080kCal$

For Proteins:

1 gram of proteins provides 4 calories

So, 3.0 gram of fat will provide = $\frac{4}{1}\times 3=12Cal=0.012kCal$

Total kilocalories per serving = [0.045 + 0.080 + 0.012] kCal = 0.137 kCal

Hence, the amount of kilocalories contained in the given serving of soup is 0.137 kCal

4 0

3 years ago