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2 years ago

PLEASE HELP!!!!! I'LL YOU BRAINIEST!!!!

Chemistry

1 answer:

Sidana [21]2 years ago

3 0

Answer:

I believe 11 is B 12 is C 13 is B and 14 is C

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During the period from about 1800 to about 1865, the atomic weights of many elements were accurately measured. Why was this impo

tatiyna

I believe Mendeleev formed his periodic table by atomic weight (nowadays we do it by atomic number) so he likely used those values.

4 0

3 years ago

The vapor pressure of liquid chloroform, CHCl3, is 100. mm Hg at 283 K. A 0.380 g sample of liquid CHCl3 is placed in a closed,

Katyanochek1 [597]

Answer:

100 mm Hg

Explanation:

From the question we are told that

The vapor pressure of CHCl3, is $P = 100 \ mmHg = \frac{100}{760}= 0.13156 \ atm$

The temperature of CHCl3 is $T = 283 \ K$

The volume of the container is $V_c = 380mL = 380 *10^{-3}\ L$

The temperature of the container is $T_c = 283 \ K$

The mass of CHCl3 is m = 0.380 g

Generally the number of moles of CHCl3 present before evaporation started is mathematically represented as

$n = \frac{m }{M }$

Here M is the molar mass of CHCl3 with the value $M = 119.38 \ g/mol$

=> $n = \frac{ 0.380 }{119.38 }$

=> $n = 0.00318 \ mols$

Generally the number of moles of CHCl3 gas that evaporated is mathematically represented as

$n_g = \frac{PV}{RT}$

Here R is the gas constant with value $R = 0.08206 L \ atm /mol\cdot K$

$n_g = \frac{0.13156* 380 *10^{-3} }{0.08206 * 283}$

$n_g = 0.00215 \ mols$

Given that the number of moles of CHCl3 evaporated is less than the number of moles of CHCl3 initially present , then it mean s that not all the liquid evaporated

At equilibrium the temperature of CHCl3 will be equal to the pressure of air so the pressure at equilibrium is 100 mmHg

4 0

3 years ago

The yeast acted as a catalyst. Explain the purpose of a catalyst in a reaction

Anna71 [15]

Answer:

The catalyst speeds up the chemical reaction.

Explanation:

The process in which chemical reaction rate increases by addition of substance is termed as a catalyst. The chemical reaction happens faster when a catalyst is present because it gives an alternative reaction pathway with lower activation energy.

The catalyst usually forms a temporary intermediate that helps in regenerating the original catalyst in the cyclic process. Yeast when added in a mixture work as a catalyst and helps with chemical reaction.

5 0

3 years ago

What is the mass percentage of silicon?

Mkey [24]

Answer: 46.743%

Explanation: what is the mass percentage of silicon? 46.743%

***If you found my answer helpful, please give me the brainliest, please give a nice rating, and the thanks ( heart icon :) ***

8 0

2 years ago

Explain how a light can be seen when sent through a colloid mixture, but not a solution.

Free_Kalibri [48]

I think the answer is that is lights up?

5 0

2 years ago