How do i read the triple beam balance?

Slow cooling of hot magma leads to the formation of ___________ crystals

Inessa05 [86]

Answer:

Slow cooling leads to the formation of large crystals. If the crystals remain undisturbed while cooling, they grow according to a regular pattern. Magma closer to the surface cools much faster than magma that hardens deep below ground. With rapid cooling, there is no time for magma to form large crystals.

Explanation:

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8 0

2 years ago

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A 21.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature ris

Blababa [14]

<u>Answer:</u> The heat capacity of calorimeter is $15.66J/^oC$

<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 ethanol = 21.8 g

Molar mass of ethanol = 46.07 g/mol

Putting values in above equation, we get:

$\text{Moles of ethanol}=\frac{21.8g}{46.07g/mol}=0.473mol$

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

$q$ = amount of heat released = ?

n = number of moles = 0.473 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction = -1235 kJ/mol = $-1235\times 10^3J/mol$ (Conversion factor: 1 kJ = 1000 J)

Putting values in above equation, we get:

$-1235\times 10^3J/mol=\frac{q}{0.473mol}\\\\q=(-1235\times 10^3J/mol\times 0.473mol)=-584.16\times 10^3J$

To calculate the heat capacity of calorimeter, we use the equation:

$q=c\Delta T$

where,

q = heat absorbed by the calorimeter = $584.16\times 10^3J$

c = heat capacity = ?

$\Delta T$ = change in temperature = $T_2-T_1=62.3^oC-25^oC=37.3^oC$

Putting values in above equation, we get:

$584.16\times 10^3J=c\times 37.3^oC\\\\c=\frac{584.16\times 10^3J}{37.3^oC}=15.66J/^oC$

Hence, the heat capacity of calorimeter is $15.66J/^oC$

4 0

4 years ago

List down the periodic table

egoroff_w [7]

Answer:

Explanation:

open picture

8 0

3 years ago

Who discovered phosphate?

iris [78.8K]

Answer:

Hennig Brand

Explanation:

4 0

3 years ago

Phosphorus pentachloride decomposes according to this equation. PCl5(g) equilibrium reaction arrow PCl3(g) + Cl2(g) An equilibri

melisa1 [442]

Answer:

PCl₅ = 0.03 X 208 = 6.24g

PCl₃ = 0.05 X 137 =6.85 g

Cl₂ = 0.03X71 = 2.13 g

Explanation:

The equilibrium constant will remain the same irrespective of the amount of reactant taken.

Let us calculate the equilibrium constant of the reaction.

Kc= $\frac{[PCl_{3}][Cl_{2}]}{[PCl_{5}]}$

Let us calculate the moles of each present at equilibrium

$moles=\frac{mass}{molarmass}$

molar mass of PCl₅=208

molar mass of PCl₃=137

molar mass of Cl₂=71

moles of PCl₅ = $\frac{mass}{molarmass}=\frac{4.13}{208}=0.02$

moles of PCl₃= $\frac{mass}{molarmass}=\frac{8.87}{137}=0.06$

moles of Cl₂ = $\frac{mass}{molarmass}=\frac{2.90}{71}=0.04$

the volume is 5 L

So concentration will be moles per unit volume

Putting values

Kc = $\frac{\frac{0.06}{5}\frac{0.04}{5}}{\frac{0.02}{5}}=0.024$

Now if the same moles are being transferred in another beaker of volume 2L then there will change in the concentration of each as follow

$PCl_{5}--->PCl_{3}+Cl_{2}$

Initial 0.02 0.06 0.04

Change -x +x +x

Equilibrium 0.02-x 0.06+x 0.04+x

Conc. (0.02-x)/2 (0.06+x)/2 (0.04+x)/2

Putting values

0.024 = $\frac{(0.06+x)(0.04+x)}{(0.02-x)2}$

Solving

$(0.024(2)(0.02-x)=(0.06+x)(0.04+x)$

$0.00096-0.048x=0.0024+x^{2}+0.1x$

$0.148x+x^{2}+0.00144=0$

x = -0.01

so the new moles of

PCl₅ = 0.02 + 0.01 =0.03

PCl₃ = 0.06-0.01 = 0.05

Cl₂ = 0.04-0.01 = 0.03

mass of each will be:

mass= moles X molar mass

PCl₅ = 0.03 X 208 = 6.24g

PCl₃ = 0.05 X 137 =6.85 g

Cl₂ = 0.03X71 = 2.13 g

5 0

4 years ago