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3 years ago

What is the density of an unknown object with a mass of 225g and a volume of 500cm3

Chemistry

1 answer:

andrezito [222]3 years ago

3 0

Answer:

0.45 g/cm3

Explanation:

Density = Mass/Volume

225g/500cm3=0.45cm3

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A solution was prepared by dissolving 2.2 g of an unknown solute in 16.7 g of CCl4. A thermal analysis was performed for this so

laila [671]

Answer:

Molar mass of unknown solute is 679 g/mol

Explanation:

Let us assume that the solute is a non-electrolyte.

For a solution with non-electrolyte solute remains dissolved in it -

Depression in freezing point of solution, $\Delta T_{f}=K_{f}.m$

where, m is molality of solute in solution and $K_{f}$ is cryogenoscopic constant of solvent.

Here $\Delta T_{f}=(-22.9^{0}\textrm{C})-(-28.7^{0}\textrm{C})=5.8^{0}\textrm{C}$

If molar mass of unknown solute is M g/mol then-

$m=\frac{\frac{2.2}{M}}{0.0167}mol/kg$

So, $5.8^{0}\textrm{C}=29.9^{0}\textrm{C}/(mol/kg)\times \frac{\frac{2.2g}{M}}{0.0167}mol/kg$

so, M = 679 g/mol

4 0

2 years ago

A sample of hydrogen gas collected over water occupied 30.0 mL at 24 °C on a day when the atmospheric pressure was 736 Torr. Wha

givi [52]

Answer:0.026ml

Explanation:

Details are found in the image attached. We must subtract the saturated vapour pressure of hydrogen gas at the given temperature from the total pressure of the hydrogen gas collected over water to obtain the actual pressure of hydrogen gas and substitute the value obtained into the general gas equation. The dry hydrogen gas has no saturated vapour pressure hence the value is substituted as given. All temperatures must be converted to Kelvin before substitution.

4 0

3 years ago

How many pints are in 53 gallons'?

geniusboy [140]

There are 424 pints in 53 gallons.

8 0

3 years ago

Read 2 more answers

The amount of energy required to heat water for a 10-minute shower (50 gallons) is 2.2125 kJ. How many calories is this?

Zigmanuir [339]

From the problem statement, this is a conversion problem. We are asked to convert from units of kilojoules to units of calories. To do this, we need a conversion factor which would relate the different units involved. We either multiply or divide this certain value to the original measurement depending on what is asked. From literature, we will find that 1 kilojoule is equal to 239 calories. We do as follows:

2.2125 kJ ( 239 calories / 1 kJ ) = 528.79 calories

6 0

3 years ago

A plot of 1/[BrO-] vs. time is linear and the slope is equal to 0.056 M-1s-1. If the initial concentration of BrO- is 0.65 M, ho

finlep [7]

Answer:

time taken for one-half of the BrO⁻ ion to react is t= 27.45 secs

Explanation:

equation of reaction

3BrO⁻(aq) → BrO₃⁻(aq) + 2Br⁻(aq) (second order reaction)

given

the slope of the graph is 0.056M⁻¹s⁻¹ = k(constant)

initial concentration [A]₀ = 0.65M

for second order reaction,we can calculate the time taken for one-half of the BrO- ion to react using:

$\frac{1}{[A]}$ = $\frac{1}{[A]}$ ₀ ⁺ k × t

where initial concentration [A]₀ = 0.65M

[A] = [A]₀÷2 = 0.325M

$\frac{1}{0.325M}$ = $\frac{1}{0.65M}$ + 0.056M⁻¹s⁻¹ × t

3.077= 1.54 + 0.056t

3.077-1.54=0.056t

1.537=0.056t

t= 27.45 secs

4 0

2 years ago