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3 years ago

32. A good way to avoid blas when collecting samples is to

Chemistry

1 answer:

Aleksandr-060686 [28]3 years ago

5 0

Provides equal odds for every member of the population to be choose as a parcipant in the study land

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g Tibet (altitude above sea level is 29,028 ft) has an atmospheric pressure of 240. mm Hg. Calculate the boiling point of water

Marina CMI [18]

Answer: The boiling point of water in Tibet is 69.9°C

Explanation:

To calculate the boiling point of water in Tibet, we use the Clausius-Clayperon equation, which is:

$\ln(\frac{P_2}{P_1})=\frac{\Delta H}{R}[\frac{1}{T_1}-\frac{1}{T_2}]$

where,

$P_1$ = initial pressure which is the pressure at normal boiling point = 1 atm = 760 mmHg (Conversion factor: 1 atm = 760 mmHg)

$P_2$ = final pressure = 240. mmHg

$\Delta H_{vap}$ = Heat of vaporization = 40.7 kJ/mol = 40700 J/mol (Conversion factor: 1 kJ = 1000 J)

R = Gas constant = 8.314 J/mol K

$T_1$ = initial temperature or normal boiling point of water = $100^oC=[100+273]K=373K$

$T_2$ = final temperature = ?

Putting values in above equation, we get:

$\ln(\frac{240}{760})=\frac{40700J/mol}{8.314J/mol.K}[\frac{1}{373}-\frac{1}{T_2}]\\\\-1.153=4895.36[\frac{T_2-373}{373T_2}]\\\\T_2=342.9K$

Converting the temperature from kelvins to degree Celsius, by using the conversion factor:

$T(K)=T(^oC)+273$

$342.9=T(^oC)+273\\T(^oC)=(342.9-273)=69.9^oC$

Hence, the boiling point of water in Tibet is 69.9°C

3 0

3 years ago

How many atoms are in two water molecules? pls and thxxxxxxxxx

arlik [135]

Answer:

A water molecule consists of three atoms; an oxygen atom and two hydrogen atoms, which are bond together like little magnets. The atoms consist of matter that has a nucleus in the centre. one mole of water contains 6.02 x 1023 MOLECULES of water But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 1024 atoms in a mole of water.Feb 12, 2003

Explanation:

7 0

3 years ago

A lab team places 0.250g of an unknown solid acid in an Erlenmeyer flask. They neutralize the solid acid with 15.0ml of 0.210 M

Otrada [13]

Answer:

Molar mass of the unknown acid is 79 grams

Explanation:

We have to first get moles in 15.0 ml of sodium hydroxide solution:

${ \sf{1 \: l \: of \:NaOH \: contains \: 0.210 \: moles }} \\ { \sf{0.015 \: l \: of \: NaOH \: contain \: (0.015 \times 0.210) \: moles }} \\ { \underline{ = 0.00315 \: moles \: of \: NaOH}}$

since mole ratio of acid : base is 1 : 1, so;

moles of acid that reacted is 0.00315 moles of the unknown acid.

then we've to get molar mass:

${ \sf{0.00315 \: moles \: of \: acid \: weigh \: 0.250 \: g}} \\ { \sf{1 \: mole \: of \: acid \: weighs \: ( \frac{1 \times 0.250}{0.00315} ) \: g}} \\ { \underline{ = 79.4 \: g \approx79 \: grams}}$

6 0

3 years ago

True or false: if two atoms are in the same group they have the same number of electron shells.

marin [14]

False: I believe if two atoms are in the same group it would not mean they have the same number of electron shells BUT it would mean that if the two atoms are in the same group they would have the same number of valence electrons.

Hoped this helped :)

7 0

3 years ago

Read 2 more answers

MAZA11189 can you solve this

Marysya12 [62]

Answer:

The answer is below

Explanation:

A) The method of extracting essential oils from aromatic plants is important however, the process of distillation is the main method for extracting the aromatic parts of plants.

B) The condenser fan plays an important role on circulating the air across the coil to facilitate heat transfer. The condenser refrigerant and pumps it to a coil in the form of a hot gas.

4 0

3 years ago