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lisabon 2012 [21]
3 years ago
12

The mass number of an atom is the number of

Chemistry
2 answers:
sergeinik [125]3 years ago
6 0

Answer:

protons plus neutrons

Explanation:

jsut the definition

AlexFokin [52]3 years ago
6 0

Answer:

protons

Explanation:

the sum of the numbers of protons and neutrons present in the nucleus of an atom

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What characteristic do all parts of the electromagnetic spectrum have in common
Elza [17]
All electromagnetic waves are amplitude, a characteristic frequency and wavelength, and the ability to travel through a vacuum at the same speed (the speed of light)
5 0
3 years ago
Write the chemical equations involved in this experiment and how that the rate of disappearance of [S2O8^2-] is proportional to
Ne4ueva [31]

S₂O₈²⁻

(aq) + 2I⁻

(aq) → I₂(aq) + 2SO₄

²⁻(aq)

2S₂O₃²⁻

(aq) + I₂(aq) → S₄O₆²⁻

(aq) + 2I⁻

(aq)

<u>Explanation:</u>

S₂O₈²⁻

(aq) + 2I⁻

(aq) → I₂(aq) + 2SO₄

²⁻(aq)

To measure the rate of this reaction we must measure the rate of concentration change of one of  the reactants or products. To do this, we will include (to the reacting S₂O₈

²⁻  and I⁻

i) a small amount of sodium thiosulfate, Na₂S₂O₃,

ii) some starch indicator.

The added Na₂S₂O₃ does not interfere with the rate of above reaction, but it does consume the I₂  as soon as it is formed.

2S₂O₃²⁻

(aq) + I₂(aq) → S₄O₆²⁻

(aq) + 2I⁻

(aq)

This reaction is much faster than the previous, so the conversion of I2 back to I⁻  is  essentially instantaneous.

rate = \frac{dI2}{dt} = \frac{1/2 [S2O3^2^-]}{t}

5 0
3 years ago
Which landscape is located at 42°N 75° W
vovikov84 [41]
The answer would be <span>Tug Hill Plateau</span>
7 0
3 years ago
Sulfur dioxide has a vapor pressure of 462.7 mm Hg at –21.0 °C and a vapor pressure of 140.5 mm Hg at –44.0 °C. What is the enth
stealth61 [152]

Answer : The value of \Delta H_{vap} is 28.97 kJ/mol

Explanation :

To calculate \Delta H_{vap} of the reaction, we use clausius claypron equation, which is:

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

where,

P_1 = vapor pressure at temperature -21.0^oC = 462.7 mmHg

P_2 = vapor pressure at temperature -44.0^oC = 140.5 mmHg

\Delta H_{vap} = Enthalpy of vaporization = ?

R = Gas constant = 8.314 J/mol K

T_1 = initial temperature = -21.0^oC=[-21.0+273]K=252K

T_2 = final temperature = 45^oC=[-41.0+273]K=232K

Putting values in above equation, we get:

\ln(\frac{140.5mmHg}{462.7mmHg})=\frac{\Delta H_{vap}}{8.314J/mol.K}[\frac{1}{252}-\frac{1}{232}]\\\\\Delta H_{vap}=28966.6J/mol=28.97kJ/mol

Therefore, the value of \Delta H_{vap} is 28.97 kJ/mol

4 0
3 years ago
A scientist has two samples of gas: The first sample contains one mole of argon atoms and has a mass of 39.948 g; the second sam
V125BC [204]

There are 6.022 × 10²³ atoms in 39.948 g of argon and 4.0026 g of helium.

Explanation:

39.945 g/mole is the molar mass of argon so 39.948 g of argon are equal to 1 mole of argon.

4.0026 g/mole is the molar mass of helium so 4.0026 g of helium are equal to 1 mole of helium.

We know that Avogadro's number tell us the number of particles in 1 mole of substance which is 6.022 × 10²³.

So in 39.948 g of argon and 4.0026 g of helium contains the same number of atoms, 6.022 × 10²³.

Learn more about:

Avogadro's number

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#learnwithBrainly

4 0
4 years ago
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