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3 years ago

Calculate with the correct number of significant figures 2.0 x 10^5 x 3.00 x 10^8

Chemistry

1 answer:

xxMikexx [17]3 years ago

3 0

Answer:

the correct answer is 17 significant figures

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When a 2.00 g sample of KCl is dissolved in water in a calorimeter that has a total heat capacity of 1.28 kJ ⋅ K − 1 , the tempe

Alchen [17]

Answer : The molar heat of solution of KCl is, 17.19 kJ/mol

Explanation :

First we have to calculate the heat of solution.

$q=c\times (\Delta T)$

where,

q = heat produced = ?

c = specific heat capacity of water = $1.28kJ/K$

$\Delta T$ = change in temperature = 0.360 K

Now put all the given values in the above formula, we get:

$q=1.28kJ/K\times 0.360K$

$q=0.4608kJ=460.8J$

Now we have to calculate the molar heat solution of KCl.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = ?

q = heat released = 460.8 J

m = mass of $KCl$ = 2.00 g

Molar mass of $KCl$ = 74.55 g/mol

$\text{Moles of }KCl=\frac{\text{Mass of }KCl}{\text{Molar mass of }KCl}=\frac{2.00g}{74.55g/mole}=0.0268mole$

Now put all the given values in the above formula, we get:

$\Delta H=\frac{460.8J}{0.0268mole}$

$\Delta H=17194.029J/mol=17.19kJ/mol$

Therefore, the molar heat of solution of KCl is, 17.19 kJ/mol

7 0

2 years ago

using the same balanced equation, what is the number of moles of carbon dioxide produced from 3.750 moles of propane?

kondor19780726 [428]

Answer:

11.25moles of CO2

Explanation:

First, let us generate a balanced equation for the reaction of propane to produce CO2. This reaction called Combustion. It is a reaction in which propane burns in air (O2) to produce CO2 and H20. The equation is given below:

C3H8 + 5O2 —> 3CO2 + 4H2O

From the equation,

1mole of C3H8 produced 3moles of CO2.

Therefore, 3.750 moles of C3H8 will produce = 3.750 x 3 = 11.25moles of CO2

5 0

2 years ago

What percentage of the mass of hydrofluoric acid (HF) is contributed by hydrogen?

Morgarella [4.7K]

This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5% as shown below:

<h3>Percent compositions:</h3>

In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:

$\% H=\frac{m_H*1}{M_{HF}}*100\%$

Where $m_H$ stands for the atomic mass of hydrogen and $M_{HF}$ for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain: