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3 years ago

What did scientists discover when they arranged elements in order of increasing atomic mass?

1 answer:

4 0

<span>The scientists discovered that when they organized elements in order of increasing atomic mass there is a pattern of repetition of properties (A). The periodic law was developed by Dmitri Mendeleev and Lothar Mayer in 1869. They worked independently of each other and both created a periodic table. They both arranged the items on the table by weight and both suggested that certain properties of the elements recur. The Mendeleev table is the most important table because the values for the atomic mass are the most accurate.</span>

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Calculate the concentration of a solution that has 6.7 moles in a volume of 0.6 liters.

Yuri [45]

Answer:

11.2 M

Explanation:

Given data:

Number of moles = 6.7 mol

Volume of solution = 0.6 L

Concentration /Molarity = ?

Solution:

Molarity:

It is number of moles of solute in to per kg or litters of solution. It can be calculated by the following formula.

Molarity = number of moles / Volume in L

Now we will put the values in formula.

Molarity = 6.7 mol / 0.6 L

Molarity = 11.2 mol/L

Molarity = 11.2 M

6 0

3 years ago

At 25 celsius, 1.00 ,ole of O2 was found to occupy a volume of 12.5 L at a pressure of 198 kPa. What value of the gas constant i

mr Goodwill [35]

Answer:

$R=8.301\frac{L*kPa}{mol*K}$

Explanation:

Hello,

In this case, assuming oxygen as an ideal gas, it is described by:

$PV=nRT$

Whereas the gas constant R is required, therefore, it is computed as shown below:

$R=\frac{PV}{nT} =\frac{198kPa*12.5L}{1.00mol*(25+273.15)K} \\\\R=8.301\frac{L*kPa}{mol*K}$

Best regards.

4 0

3 years ago

Calculate the mass percent for all components in a solution containing the following. 0.350 Kg of water, 5.4 moles of ammonia an

Alina [70]

Answer:

% Water = 54.96%

% Ammonia = 0.14%

% Cobalt (II) Nitrate = 30.62%

Explanation:

To calculate mass percent, first we need to <u>calculate the total mass of the mixture</u>:

Mass Water ⇒ 0.350 kg Water = 350 g water

Mass Ammonia⇒We use ammonia's molar mass⇒5.4 mol * 17 g/mol = 91.8 g

Mass cobalt (II) nitrate ⇒ 195.0 g

Total Mass = Mass Water + Mass Ammonia + Mass Cobalt Nitrate

Total Mass = 350 g+ 91.8 g+ 195 g = 636.8 g

To calculate each component's mass percent, we divide its mass by the total mass and multiply by 100:

% Water ⇒ 350/636.8 * 100% = 54.96%

% Ammonia ⇒ 91.8/636.8 * 100% = 0.14%

% Cobalt (II) Nitrate ⇒ 195/636.8 * 100% = 30.62%

8 0

3 years ago

A chemist titrates 160.0mL of a 0.3403M aniline C6H5NH2 solution with 0.0501M HNO3 solution at 25°C . Calculate the pH at equiva

maxonik [38]

Answer : The pH of the solution is, 5.24

Explanation :

First we have to calculate the volume of $HNO_3$

Formula used :

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the initial molarity and volume of $C_6H_5NH_2$ .

$M_2\text{ and }V_2$ are the final molarity and volume of $HNO_3$ .

We are given:

$M_1=0.3403M\\V_1=160.0mL\\M_2=0.0501M\\V_2=?$

Putting values in above equation, we get:

$0.3403M\times 160.0mL=0.0501M\times V_2\\\\V_2=1086.79mL$

Now we have to calculate the total volume of solution.

Total volume of solution = Volume of $C_6H_5NH_2$ + Volume of $HNO_3$

Total volume of solution = 160.0 mL + 1086.79 mL

Total volume of solution = 1246.79 mL

Now we have to calculate the Concentration of salt.

$\text{Concentration of salt}=\frac{0.3403M}{1246.79mL}\times 160.0mL=0.0437M$

Now we have to calculate the pH of the solution.

At equivalence point,

$pOH=\frac{1}{2}[pK_w+pK_b+\log C]$

$pOH=\frac{1}{2}[14+4.87+\log (0.0437)]$

$pOH=8.76$

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-8.76\\\\pH=5.24$

Thus, the pH of the solution is, 5.24

4 0

3 years ago

Science science science science

In-s [12.5K]

Answer:

Sorry

Explanation:

Sorry this is not chemistry but I always try to answer but this time I can't I am so so sorry

4 0

3 years ago

Read 2 more answers