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2 years ago

How much heat is required to decompose 25.5 grams of NaHCO3? 2NaHCO3(s) + 129 kJ 2Na2CO3(s) + H2O(

1 answer:

4 0

To determine the heat required in order to decompose a certain amount of a substance, we need information on the heat needed to decompose one mole of the substance. This value are readily available online and other sources. For this reaction, the heat needed is 129 kJ per 2 mol of NaHCO3. We calculate as follows:

129 KJ / 2 mol NaHCO3 (1 mol / 84.01 g ) (25.5 g NaHCO3 ) = 19.58 kJ of heat is needed.

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A football is inflated to 12psi at 20°C What is the new pressure in the football

Radda [10]

Answer: The new pressure is 3 psi.

Explanation:

Given: $P_{1}$ = 12 psi, $T_{1} = 20^{o}C$

$P_{2}$ = ?, $T_{2} = 5^{o}C$

Formula used is as follows.

$\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}\\\frac{12 psi}{20^{o}C} = \frac{P_{2}}{5^{o}C}\\P_{2} = \frac{12 psi \times 5^{o}C}{20^{o}C}\\= 3 psi$

Thus, we can conclude that the new pressure is 3 psi.

7 0

2 years ago

onvert the value of Kc to a value of Kp for the following reaction: N2(g)+3H2(g)⇌2NH3(g) Kc = 0.50 at 400 °C.

ale4655 [162]

Answer:

$K_p= 0.00016$

Explanation:

The relation between Kp and Kc is given below:

$K_p= K_c\times (RT)^{\Delta n}$

Where,

Kp is the pressure equilibrium constant

Kc is the molar equilibrium constant

R is gas constant

T is the temperature in Kelvins

Δn = (No. of moles of gaseous products)-(No. of moles of gaseous reactants)

For the first equilibrium reaction:

$N_2_{(g)}+3H_2_{(g)}\rightleftharpoons2NH_3_{(g)}$

Given: Kc = 0.50

Temperature = $400^oC=[400+273]K=673K$

R = 0.082057 L atm.mol⁻¹K⁻¹

Δn = (2)-(3+1) = -2

Thus, Kp is:

$K_p= 0.50\times (0.082057\times 673)^{-2}$

$K_p= 0.00016$

6 0

2 years ago

Which of the following statements best describes the current atomic theory

blagie [28]

You did not provide possible answers, but one possible might be that the current atomic theory is so sound and plausible that there should not be anything that could change it in the near future.

3 0

3 years ago

The gasses in a hair spray can are at temperature 300k and a pressure of 30 atm, it

Sergeeva-Olga [200]

Answer:

900 K

Explanation:

Recall the ideal gas law:

$\displaystyle PV = nRT$

Because only pressure and temperature is changing, we can rearrange the equation as follows:
$\displaystyle \frac{P}{T} = \frac{nR}{V}$

The right-hand side stays constant. Therefore:

$\displaystyle \frac{P_1}{T_1} = \frac{P_2}{T_2}$

The can explodes at a pressure of 90 atm. The current temperature and pressure is 300 K and 30 atm, respectively.

Substitute and solve for <em>T</em>₂:

$\displaystyle \begin{aligned} \frac{(30\text{ atm})}{(300\text{ K})} & = \frac{(90\text{ atm})}{T_2} \\ \\ T_2 & = 900\text{ K}\end{aligned}$

Hence, the temperature must be reach 900 K.

7 0

2 years ago

List 2 extensive properties and 3 intensive properties of a 5.0g, 1 cm3 cube of silver

jeka57 [31]

Properties of matter can be broadly classified into two categories:

Physical properties which usually involve a change in the state of matter and Chemical properties which involve a change in the chemical composition of matter.

Now, physical properties can be further classified as:

Extensive: these depend on the amount of the substance, eg: mass, volume

Intensive: these do not depend on the amount of the substance eg: density, color, melting point, boiling point

Here we are given a 5.0 g and 1 cm3 silver cube :

Therefore:

Extensive properties are-

1) Mass of silver = 5.0 g

2) Volume of silver = 1 cm3

Intensive properties are:

1) Density of silver = mass/volume = 5.0 g/ 1 cm3 = 5.0 g/cm3

2) Melting point of silver = 962 C

3) Color = white/gray

3 0

3 years ago