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butalik [34]
3 years ago
5

Which of the following numbers count as exact numbers and do not count when determining significant figures in a calculation? 1.

Density: 3.7 g/mL 2. Volume: 1000 mL/L 3. Length: 2.54 cm/in 4. Speed: 65.2 km/hr 5. Number: 14 aardvarks 6. Mass: 38.741 g
Chemistry
1 answer:
rewona [7]3 years ago
4 0

Answer :

(1) Density do not count as exact number.

(2) Volume count as exact number.

(3) Length count as exact number.

(4) Speed do not count as exact number.

(5) Number count as exact number.

(6) Mass do not count as exact number.

Explanation :

Exact numbers : It is a defined or integer value which comes from counting numbers of objects.

They have an infinite number of significant figures.

For example : 12 eggs in a dozen, 1000 g in a kilogram and 2.54 cm in an inch.

Now we have to determine the following numbers count as exact numbers.

(1) Density : 3.7 g/mL

Density do not count as exact number.

(2) Volume : 1000 mL/L

Volume count as exact number.

(3) Length : 2.54 cm/in

Length count as exact number.

(4) Speed : 65.2 km/hr

Speed do not count as exact number.

(5) Number : 14 aardvarks

Number count as exact number.

(6) Mass : 38.741 g

Mass do not count as exact number.

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I’ve gotten the answer as x=.478 but when plugging back in, .46/.478 ≠ .22. Help please
ivanzaharov [21]

Answer:

15. 2.66 moles .

16. 2.09L.

Explanation:

Molarity of a solution is simply defined as the mole of solute per unit litre of the solvent. Mathematically, it is represented as:

Molarity = mole /Volume.

With the above formula, let us answer the questions given above

15. Data obtained from the question include the following:

Volume of solution = 1.4L

Molarity = 1.9M

Mole of solute =.?

Molarity = mole /Volume

1.9 = mole / 1.4

Cross multiply

Mole = 1.9 x 1.4

Mole = 2.66 moles

Therefore, the mole of the solute present in the solution is 2.66 moles.

16. Data obtained from the question include the following:

Mole of solute = 0.46 mole

Molarity = 0.22M

Volume of solvent (water) =.?

Molarity = mole /Volume

0.22 = 0.46/Volume

Cross multiply

0.22 x Volume = 0.46

Divide both side 0.22

Volume = 0.46/0.22

Volume = 2.09L

Therefore, 2.09L of water is required.

6 0
3 years ago
Which formula is an empirical formula?
poizon [28]
<h2>Hello!</h2>

The answer is:

The empirical formula is the option B. NH_{3}

<h2>Why?</h2>

The empirical formula of a compound is the simplest formula that can be written. On the opposite, the molecular formula involves a variant of the same compound, but it can be also simplified to an empirical formula.

MolecularFormula=n(EmpiricalFormula)

We are looking for a formula that cannot be simplified by dividing the number of molecules/atoms that conforms the compound.

Let's discard option by option in order to find which formula is an empirical formula (cannot be simplified)

A. N_{2}O_{4}

It's not an empirical formula, it's a molecular formula since it can be obtained by multiplying the empirical formula of the same compound.

N_{2}O_{4}=2(NO_{2})

B. NH_{3}

It's an empirical formula since it cannot be obtained by the multiplication of a whole number and the simplest formula. It's the simplest formula that we can find of the compound.

C. C_{3}H_{6}

It's not an empirical formula, it's a molecular formula since it can be obtained by multiplying the empirical formula of the same compound.

C_{3}H_{6}=3(CH_{2})

D. P_{4}O_{10}

It's not an empirical formula, it's a molecular formula since it can be obtained by multiplying the empirical formula of the same compound.

P_{4}O_{10}=2(P_{2}O_{5})

Hence, the empirical formula is the option B. NH_{3}

Have a nice day!

6 0
3 years ago
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Dafna11 [192]

Answer:

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8 0
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Diano4ka-milaya [45]

Answer:

3.14

Explanation:

A student was comparing two samples with an equal number of carbon atoms. One sample contained only Carbon-12 atoms. One sample contained only Carbon-14 atoms, which contain two more neutrons than Carbon-12 atoms. The student measured the mass of each sample and testing the reactivity of each sample.

Required:

What would best describe the results of the investigation?

3 0
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