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3 years ago

The atomic mass of an element is calculated using the

1 answer:

6 0

The atomic mass of an element is calculated using its masses and the ratios of its naturally occurring isotopes. The answer is number 3. The rest of the choices do not answer the question above.

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Which statement best describes the collisions of gas particles according to the kinetic-molecular theory?

allochka39001 [22]

B. As particles travel in straight lines, their paths sometimes meet, and then they bounce apart with no gain or loss of energy.

Explanation:

The best statement that describes the collision of gas particles according to the kinetic-molecular theory is that as particles travel in straight lines, their paths sometimes meet and then they bounce apart with no gain or loss of energy.

The kinetic molecular theory is used to explain the forces between molecules and their energy.

One of the postulate suggests that, when molecules collide with each other, or with the wall of the container, there is no loss or gain of energy.

Molecules are independent of one another and that forces of attraction and repulsion between molecules are negligible.

Learn more:

Particle collision brainly.com/question/6439920

#learnwithBrainly

4 0

3 years ago

A histidine is involved in an interaction with a glutamic acid that stabilizes the charged form of the histidine, such that the

Greeley [361]

Answer:

pKa of the histidine = 9.67

Explanation:

The relation between standard Gibbs energy and equilibrium constant is shown below as:

$\Delta{G^0} =-RT \ln \frac{[His]}{[His+]}$

R is Gas constant having value = 0.008314 kJ / K mol

Given temperature, T = 293 K

Given, $\Delta{G^0}=15\ kJ/mol$

So, Applying in the equation as:-

$15\ kJ/mol=-0.008314\ kJ/Kmol\times 293\ K\times \ln \frac{[His]}{[His+]}$

Thus,

$15\ kJ/mol=-0.008314\ kJ/Kmol\times 293\ K\times \ln \frac{[His]}{[His+]}$

$\frac{[His]}{[His+]}=e^{\frac{15}{-0.008314\times 293}$

$\frac{[His]}{[His+]}=0.00211$

Also, considering:-

$pH=pKa+log\frac{[His]}{[His+]}$

Given that:- pH = 7.0

So, $7.0=pKa+log0.00211$

pKa of the histidine = 9.67

8 0

2 years ago

The stock concentration of NaOH is 0.5M. 0.5M = 0.500mol/1.0L.

valentinak56 [21]

Answer:a) 0.1 mole. b) 4g. c) 2% d) 196 mL

Explanation: in 200mL , 0.1mole

mw NaOH = 40g/mol —> 4g in 0.1 mole

4g in 200mL so 2g in 100mL

density NaOH = 1g/mL so if 4g in 200 mL, 4mL , 196 mL water

5 0

2 years ago

A student attempted to identify an unknown compound by the method used in the experiment. She found that when she heated the sam

yanalaym [24]

Na2CO3 + 2Cl- ⇒ 2NaCl + CO3^-2

1 mole of Na2CO3 = 106 g 
2 moles of NaCl = 2 x 58.4
= 116.8 g
Na2CO3 would increase by 116.8 / 106 = 1.10 to form 2NaCl.
0.4862 g x 1.10 = 0.515 grams of NaCl.

K2CO3 + 2Cl- ⇒ 2KCl + CO3^-2
1 mole of K2CO3 = 138.2 g 
2 moles of KCl = 149.1 

K2CO3 would increase by 149.1 /138.2 = 1.079 to form 2KCl

 0.4862 x 1.079 = 0.5246 g

3 0

3 years ago

Read 2 more answers

Briefly describe how a potentiometric pHmeter works. (Hint: Describe how the pH meter measures the amount of H+ or OH- ions in a

KengaRu [80]

Answer:

Indicators show changes in the pH of a solution

Explanation:

A pH meter is an instrument that measures the hydrogen-ion activity in aqueous solutions, indicating the acidity or alkalinity of the solution expressed as pH .The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, hence the pH meter is sometimes referred to as a potentiometric pH meter. Potentiometric pH meters measure the voltage between two electrodes and display the result converted into the corresponding pH value. The instrument comprises of a simple electronic amplifier and a pair of electrodes, or alternatively a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested.

Organic indicators are chemical species that change their colour in response to changes in the pH of the solution. This implies that the anionic and protonated forms of the indicator possess different colours. Hence the colour changes in acidic, basic and neutral solutions. The images attached indicate the colour changes in phenolphthalein and methyl orange in acidic and basic media accordingly.

4 0

2 years ago