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Fudgin [204]
3 years ago
15

38 An aluminum sample has a mass of 80.01 g and a density of 2.70 g/cm3. According to the data, to what number of significant fi

gures should the calculated volume of the aluminum sample be expressed?(1) 1 (3) 3
(2) 2 (4) 4
Chemistry
2 answers:
Rufina [12.5K]3 years ago
4 0

Answer:

C. 3

Explanation:

To determine the number of significant figures use this memory aid:  If the decimal is Absent count from the Atlantic (right side).  If the decimal is Present count from the Pacific (left side).   Start counting at the first non-zero digit.

The result of a calculation can only contain the lowest number of significant figures given in the problem.  2.70 has 3 significant figures.

Furkat [3]3 years ago
3 0
The answer is (3) 3. The calculation rule of significant figures is when multiplication and division, the significant figures of result is equal to the least of the numbers involved. The significant figure of 2.70 and 80.01 is 3 and 4.
You might be interested in
How many liters of ammonia (NH3), at 3.2 atm and 23C, must be used to produce of 2.65 grams of calcium hydride (CaH2). 6 Ca(s)
7nadin3 [17]

Answer:

The answer to your question is    V = 0.32 L

Explanation:

Data

Volume of NH₃ = ?

P = 3.2 atm

T = 23°C

mass of CaH₂ = 2.65 g

Balanced chemical reaction

               6Ca  +  2NH₃   ⇒   3CaH₂  +  Ca₃N₂

Process

1.- Convert the mass of CaH₂ to moles

-Calculate the molar mass of CaH₂

 CaH₂ = 40 + 2 = 42 g

                             42 g ------------------ 1 mol

                              2.65 g --------------  x

                              x = (2.65 x 1)/42

                              x = 0.063 moles

2.- Calculate the moles of NH₃

                     2 moles of NH₃ --------------- 3 moles of CaH₂

                      x                        --------------- 0.063 moles

                                x = (0.063 x 2) / 3

                                x = 0.042 moles of NH₃

3.- Convert the °C to °K

Temperature = 23°C + 273

                      = 296°K

4.- Calculate the volume of NH₃

-Use the ideal gas law

              PV = nRT

-Solve for V

                V = nRT / P

-Substitution

                V = (0.042)(0.082)(296) / 3.2

-Simplification

               V = 1.019 / 3.2

-Result

               V = 0.32 L

7 0
3 years ago
Which best describes an element? A pure substance. A type of a mixture. A pure compound. An impure substance.
mr Goodwill [35]

a pure compound because an element is untouched and is just itself

7 0
3 years ago
Read 2 more answers
What is water's density at 93 ∘C? Assume a constant coefficient of volume expansion. Express your answer with the appropriate un
Ganezh [65]

Answer:

982.5 kg/m³

Explanation:

When the temperature of a fluid increases, it dilates, and because of the variation of the volume, it's density will vary too. The density can be calculated by the expression:

ρ₁ = ρ₀/(1 + β*(t₁ - t₀))

Where ρ₁ is the final density, ρ₀ the initial density, β is the constant coefficient of volume expansion, t₁ the final temperature, and t₀ the initial temperature.

At t₀ = 4°C, the water desity is ρ₀ = 1,000 kg/m³. The value of the constant for water is β = 0.0002 m³/m³ °C, so, for t₁ = 93°C

ρ₁ = 1,000/(1 + 0.0002*(93 - 4))

ρ₁ = 1,000/(1+ 0.0178)

ρ₁ = 982.5 kg/m³

3 0
3 years ago
The rate constant for the second-order reaction: 2NOBr(g) → 2NO(g) + Br2(g) is 0.80/(M · s) at 10°C. Starting with a concentrati
a_sh-v [17]

Answer : The concentration of NOBr after 95 s is, 0.013 M

Explanation :

The integrated rate law equation for second order reaction follows:

k=\frac{1}{t}\left (\frac{1}{[A]}-\frac{1}{[A]_o}\right)

where,

k = rate constant = 0.80M^{-1}s^{-1}

t = time taken  = 95 s

[A] = concentration of substance after time 't' = ?

[A]_o = Initial concentration = 0.86 M

Now put all the given values in above equation, we get:

0.80=\frac{1}{95}\left (\frac{1}{[A]}-\frac{1}{(0.86)}\right)

[A] = 0.013 M

Hence, the concentration of NOBr after 95 s is, 0.013 M

4 0
3 years ago
A cylinder was charged with 1.25 atm of oxygen gas, 6.73 atm of argon, and 0.895 atm of xenon. What is the mole fraction of each
katrin2010 [14]

Considering the Dalton's partial pressure, the mole fraction of each gas is:

  • x_{oxygen}= 0.14
  • x_{argon}= 0.76
  • x_{xenon}= 0.10

<h3>Dalton's partial pressure</h3>

The pressure exerted by a particular gas in a mixture is known as its partial pressure.

So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

P_{T} =P_{1} +P_{2} +...+P_{n}

where n is the amount of gases in the gas mixture.

This relationship is due to the assumption that there are no attractive forces between the gases.

Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. The mole fraction is a dimensionless quantity that expresses the ratio of the number of moles of a component to the number of moles of all the components present.

So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:

P_{A} =x_{A} P_{T}

In summary, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.

Mole fraction of each gas

In this case, you know that:

  • P_{oxygen }= 1.25 atm
  • P_{argon}= 6.73 atm
  • P_{xenon}= 0.895 atm
  • P_{T} =P_{oxygen} +P_{argon}+P_{xenon}= 1.25 atm + 6.73 atm + 0.895 atm= 8.875 atm

Then:

  • P_{oxygen} =x_{oxygen} P_{T}
  • P_{argon} =x_{argon} P_{T}
  • P_{xenon} =x_{xenon} P_{T}

Substituting the corresponding values:

  • 1.25 atm= x_{oxygen} 8.875 atm
  • 6.73 atm= x_{argon} 8.875 atm
  • 0.895 atm= x_{xenon} 8.875 atm

Solving:

  • x_{oxygen}= 1.25 atm÷ 8.875 atm= 0.14
  • x_{argon}= 6.73 atm÷ 8.875 atm= 0.76
  • x_{xenon}= 0.895 atm÷ 8.875 atm=0.10

In summary, the mole fraction of each gas is:

  • x_{oxygen}= 0.14
  • x_{argon}= 0.76
  • x_{xenon}= 0.10

Learn more about Dalton's partial pressure:

brainly.com/question/14239096

brainly.com/question/25181467

brainly.com/question/14119417

#SPJ1

3 0
2 years ago
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