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Iteru [2.4K]
3 years ago
9

The mass number of an atom is equal to which of the following?

Chemistry
1 answer:
seropon [69]3 years ago
5 0

the answer is c, the number of protons plus the number of neutrons in a nucleus

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The energy transferred between samples of matter because of a difference in their temperatures is called a. heat. b. thermochemi
Evgesh-ka [11]

Answer:

The energy transferred between samples of matter because of a difference in their temperatures is called a. heat.

Explanation:

The first law of thermodynamics establishes that when two bodies with different temperatures are put in contact they will find thermic equilibrium to a final temperature by transferring heat. Thus the correct answer is (a).

Thermochemistry is the study of the transformations of heat energy on the chemical reactions. Chemical kinetics is the study of the rate of chemical reactions. And temperature is the measure of the heat.

8 0
3 years ago
When 2.0 mol of methanol is dissolved in 45 grams of water, what is the mole fraction of methanol
kaheart [24]

The mole fraction of methanol in the mixture is 0.444

We'll begin by calculating the number of mole of water.

  • Mass of water = 45 g
  • Molar mass of water = 18 g/mol
  • Mole of water =?

Mole = mass / molar mass

Mole of water = 45 / 18

Mole of water = 2.5 moles

Finally, we shall determine the mole fraction of methanol.

  • Mole of water = 2.5 moles
  • Mole of methanol = 2 moles
  • Total mole = 2 + 2.5 = 4.5 moles

Mole fraction of methanol =?

Mole fraction = mole / total mole

Mole fraction of methanol = 2 / 4.5

Mole fraction of methanol = 0.444

Thus, the mole fraction of methanol is 0.444

Learn more about mole fraction:

brainly.com/question/15444997

7 0
3 years ago
The time necessary for the decay of one- half sample of a radioactive substance is a _____. mass defect daughter half life nucli
Mazyrski [523]

Answer: half life

Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:

t=\frac{2.303}{k}\hspace{1mm}log\frac{x}{a}

t= time required

k= disintegration constant

x= amount of substance left after time t

a= initial amount of substance

when one half of the sample is decayed, one half of the sample remains and t can be represented as t_{1/2}

at t= t_{1/2}, x=\frac{a}{2}

t_{1/2}=\frac{2.303}{k}\hspace{1mm}log\frac{a/2}{a}

t_{1/2}=\frac{0.693}{k}

3 0
3 years ago
Read 2 more answers
A sample of a pure element has a mass of 45.6g and contains 4.19 x 10 23 atoms. Identify the element.
max2010maxim [7]
<h2>Answer:</h2>

    ZINC

<h2>Explanation:</h2>

<em>To identify the element based on the informartion given, we have to find the molar mass since this mass is unique to each element.</em>

            Molar mass = mass ÷ moles

<em>We already know the mass based on the question, as such we now need to find the # of moles.</em>

           Since 1 mole contains 6.02214 × 10²³ atoms

      then let  x moles contain 4.19 × 10²³ atoms <em>(given in the question)</em>

<em>     </em><em> </em>   ⇒   x =  (4.19 × 10²³ atoms  ×  1 mol) ÷ 6.02214 × 10²³ atoms

              x  =  0.69577 mol

<em>Now that we have the moles we can substitute it into the molar mass equation and solve for the molar mass.</em>

           ⇒ molar mass = 45.6 g ÷ 0.69577 mol

           ⇒ molar mass ≈  65.54 g/mol

                    This molar mass is closest to that of ZINC.

7 0
3 years ago
A 60 and N net force is applied to a 12 kg box which is the acceleration of the box?
GarryVolchara [31]

The relation between force and mass and acceleration is

Force = mass X acceleration

The SI unit will be

Force = Newton

mass =kg

acceleration=\frac{m}{s^{2} }

thus

acceleration = \frac{Force}{mass}

putting values

acceleration=\frac{60 N}{12kg}=5\frac{m}{s^{2} }

Thus the acceleration will be

5\frac{m}{s^{2} }

6 0
3 years ago
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