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3 years ago

Convert a pressure of 250 torr to atm a) 0.266 atm b) 0.279 atm c) 0.329 atm d) 0.297 atm

Chemistry

1 answer:

goblinko [34]3 years ago

5 0

Answer:

Explanation:

1atm=760torr

X=250torr

Cross multiply

760torrX=250torr*atm

Divide both sides by 760torr

X=250torr*atm/760torr

X=0.32895atm

X=0.329atm

Option C is collect

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You are given two beakers, distilled water, two hot plates, two thermometers and salt. These materials are enough in order to test the effect of salt in the boiling point water. To do this, you set up two beakers. In one of the beakers, you add pure distilled water and nothing else. For the other beaker, you put a solution of salt and water. You place these beakers on separate hot plates and place inside the beakers the thermometers. You heat these substances until they boil and then you measure the boiling points of the substances. You would observe that the boiling point of the solution would have a higher boiling point than the pure liquid.

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4 years ago

Five ?L of a 10-to-1 dilution of a sample were added to 5mL of Bradford reagent. The absorbance at 595 nm was 0.78 and,according

Tomtit [17]

Answer:

0.03g/mL

Explanation:

Given parameters include:

Five μL of a 10-to-1 dilution of a sample; This implies the Volume of dilute sample is given as 5 μL

Dilution factor = 10-to-1

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We need to first determine the concentration of the diluted sample which is required in calculating the protein concentration of the original solution.

So, to determine the concentration of the diluted sample, we have:

concentration of diluted sample = $\frac{mass}{volume}$

= $\frac{0.015 mg}{ 5 \alpha L}$ (where ∝ was use in place of μ in the expressed fraction)

= 0.003 mg/μL

The dilution of the sample is from 10-to-1 indicating that the original concentration is ten times higher; as such the protein concentration of the original solution can be calculated as:

protein concentration of the original solution = 10 × concentration of the diluted sample.

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3 years ago

It takes

poizon [28]

The maximum wavelength that can break a Cl-Cl bond is 494 nm.

Energy to break 1 Cl-Cl bond

Energy = (242 kJ/1 mol) × (1000 J/1 kJ) × (1 mol/6.022 × 10²³ bonds)

= 4.019 × 10⁻¹⁹ J/bond

Wavelength of photon

E = hf = (hc)/λ

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4 years ago

Which of the following work mostly severaly affect a human population

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3 years ago

6. The graph below shows the heating curve for ethanol (from –200C to 150C). Calculate the amount of heat (kJ) required for each

Kazeer [188]

This problem is providing the heating curve of ethanol showing relevant data such as the initial and final temperature, melting and boiling points, enthalpies of fusion and vaporization and specific heat of solid, liquid and gaseous ethanol, so that the overall heat is required and found to be 1.758 kJ according to:

<h3>Heating curves:</h3>

In chemistry, we widely use heating curves in order to figure out the required heat to take a substance from a temperature to another. This process may involve sensible heat and latent heat, when increasing or decreasing the temperature and changing the phase, respectively.

Thus, since ethanol starts off solid and end up being a vapor, we will find five types of heat, three of them related to the heating-up of ethanol, firstly solid, next liquid and then vapor, and the other two to its fusion and vaporization as shown below:

$Q_T=Q_1+Q_2+Q_3+Q_4+Q_5$

Hence, we begin by calculating each heat as follows, considering 1 g of ethanol is equivalent to 0.0217 mol:

$Q_1=0.0217mol*111.5\frac{J}{mol*\°C}[(-114.1\°C)-(-200\°C)] *\frac{1kJ}{1000J} =0.208kJ\\
\\
Q_2=0.0217mol*4.9\frac{kJ}{mol} =0.106kJ\\
\\
Q_3=0.0217mol*112.4\frac{J}{mol*\°C}[(78.4\°C)-(-114.1\°C)] *\frac{1kJ}{1000J} =0.470kJ\\
\\
Q_4=0.0217mol*38.6\frac{kJ}{mol} =0.838kJ\\
\\
Q_5=0.0217mol*87.5\frac{J}{mol*\°C}[(150\°C)-(78.4\°C)] *\frac{1kJ}{1000J} =0.136kJ$

Finally, we add them up to get the result:

$Q_T=0.208kJ+0.106kJ+0.470kJ+0.838kJ+0.136kJ\\
\\
Q_T=1.758kJ$

Learn more about heating curves: brainly.com/question/10481356

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