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3 years ago

The purpose of an indicator is to

2 answers:

8 0

Chemical indicators are used to identify when a reaction has undergone a chemical change or if it has reached completion.

Korvikt [17]3 years ago

8 0

Test and determine the pH values of unknown solutions

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Explain how you will seprate a mixture gari and sugar

Karo-lina-s [1.5K]

Answer:

The sugar would dissolve in water. You could then pour off the solution and wash the remaining sand with a bit more water. Heat the water to evaporate it from the sugar, and the two are separated.

Explanation:

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4 0

3 years ago

A sample of ideal gas has a volume of 0.500-L at 25.0o C and 1.20 atm pressure. What is the volume at 75.0o C and 3.60 atm?

sergeinik [125]

Answer:

.500

Explanation:

Use the ideal gas law equation: PV = nRT

Plug in the initial values given:

P = 1.2 atm

V = .500 L

n = number of moles

R = Gas Constant 8.314

T = 25.0 C

(1.2)(.5) = n(8.314)(25)

solving for n we get .00289

Now use the same equation with the new values solving for V

(3.6)V = (.00289)(8.314)(75.0)

V = .4999999 ROund to .500

3 0

3 years ago

A gas has a pressure of 760 torr at 21 degrees Celsius. What is the pressure of the gas at 250 degree Celsius.

weeeeeb [17]

Answer:

Given,

P1=760 torr

T1=21°C

T2=250°C

P2=?

Solution,

According to Gay-Lussac's Law or Third Gas Law,

P1T2=P2T1

760×250=21×P2

P2=9047 torr

9047 is the pressure of the gas at 250 degree Celsius.

7 0

3 years ago

Read 2 more answers

Calculate the amount of heat energy in KJ required to convert 45.0 g of ice at -15.5'C to steam at 124.0°C. (Cwater 118 Jig'c, G

dangina [55]

Answer : The enthalpy change or heat required is, 139.28775 KJ

Solution :

The conversions involved in this process are :

$(1):H_2O(s)(-15.5^oC)\rightarrow H_2O(s)(0^oC)\\\\(2):H_2O(s)(0^oC)\rightarrow H_2O(l)(0^oC)\\\\(3):H_2O(l)(0^oC)\rightarrow H_2O(l)(100^oC)\\\\(4):H_2O(l)(100^oC)\rightarrow H_2O(g)(100^oC)\\\\(5):H_2O(g)(100^oC)\rightarrow H_2O(g)(124^oC)$

Now we have to calculate the enthalpy change.

$\Delta H=[m\times c_{p,s}\times (T_{final}-T_{initial})]+n\times \Delta H_{fusion}+[m\times c_{p,l}\times (T_{final}-T_{initial})]+n\times \Delta H_{vap}+[m\times c_{p,g}\times (T_{final}-T_{initial})]$

where,

$\Delta H$ = enthalpy change or heat required = ?

m = mass of water = 45 g

$c_{p,s}$ = specific heat of solid water = $2.09J/g^oC$

$c_{p,l}$ = specific heat of liquid water = $4.18J/g^oC$

$c_{p,g}$ = specific heat of liquid water = $1.84J/g^oC$

n = number of moles of water = $\frac{\text{Mass of water}}{\text{Molar mass of water}}=\frac{45g}{18g/mole}=2.5mole$

$\Delta H_{fusion}$ = enthalpy change for fusion = 6.01 KJ/mole = 6010 J/mole

$\Delta H_{vap}$ = enthalpy change for vaporization = 40.67 KJ/mole = 40670 J/mole

Now put all the given values in the above expression, we get

$\Delta H=[45g\times 4.18J/gK\times (0-(-15.5))^oC]+2.5mole\times 6010J/mole+[45g\times 2.09J/gK\times (100-0)^oC]+2.5mole\times 40670J/mole+[45g\times 1.84J/gK\times (124-100)^oC]$

$\Delta H=139287.75J=139.28775KJ$ (1 KJ = 1000 J)

Therefore, the enthalpy change is, 139.28775 KJ

3 0

3 years ago

Please help need answer asp

devlian [24]

That's a heterogeneous mixture because not all the molecules are the same

8 0

3 years ago