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3 years ago

Is this correct please help?

Chemistry

1 answer:

iren [92.7K]3 years ago

7 0

Answer:

$\boxed {\tt Number \ and \ unit}$

Explanation:

The two requirements for a measurement are a <u>number</u> and a <u>unit.</u>

For example, here is a measurement:

38.6 cm

The <u>number</u> is 38.6 and the <u>unit</u> is cm, or centimeters.

Therefore, both <em>number </em>and <em>unit</em> are correct.

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Each isotope has a unique half-life. The half-life of an isotope is the time taken for half of the starting quantity to decay (w

Tems11 [23]

Answer:

b. 17,190

Explanation:

Using the formula for C-14 dating,

$t=\dfrac{ln(\dfrac{N}{N_0})t_\frac{1}{2} }{-0.693}$

where Present Value N =1/8 of Parent Sample

Initial Value, $N_0$ =1

Half Life, $t_\frac{1}{2}$ =5730 years

$t=\dfrac{ln(\dfrac{1/8}{1})5730}{-0.693}$

=17,190

Therefore the fossil is about 17190 years old.

7 0

3 years ago

Need help ASAP!! What is a function mitochondrion

NISA [10]

Answer:

powerhouse of the cell

Explanation:

Mitochondria produce ATP, a necessary sugar that runs the cell

3 0

3 years ago

Hermit crabs and anemones have a mutualistic relationship. Which of these statements best describes how they interact?

liubo4ka [24]

Answer: anemones cannot move very quickly, but they can sting predators. When an anemone is riding on a hermit crab's shell, the anemone protects the crab from predators.

Explanation:

5 0

3 years ago

3.5g of a Certain compound X, known to be made of carbon, hydrogen, and perhaps oxygen, and to have a molecular molar mass of 15

shutvik [7]

Answer:

C₅H₁₀O₅

Explanation:

1. Calculate the mass of each element in 2.78 mg of X.

(a) Mass of C

$\text{Mass of C} = \text{5.13 g CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{1.400 g C}$

(b) Mass of H

$\text{Mass of H} = \text{2.10 g H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g H$_{2}$O}} = \text{0.2349 g H}$

(c) Mass of O

Mass of O = 3.5 - 1.400 - 0.2349 = 1.87 g

2. Calculate the moles of each element

$\text{Moles of C = 1400 mg C}\times\dfrac{\text{1 mmol C}}{\text{12.01 mg C }} = \text{116.6 mmol C}\\\\\text{Moles of H = 234.9 mg H} \times \dfrac{\text{1 mmol H}}{\text{1.008 mg H}} = \text{233.1 mmol H}\\\\\text{Moles of O = 1870 mg O} \times \dfrac{\text{1 mmol O}}{\text{16.00 mg O}} = \text{116 mmol O}$

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

$\text{C: } \dfrac{116.6}{116.6}= 1\\\\\text{H: } \dfrac{233.1}{116.6} = 1.999\\\\\text{O: } \dfrac{116}{116.6} = 1.00$

4. Round the ratios to the nearest integer

C:H:O = 1:2:1

5. Write the empirical formula

The empirical formula is CH₂O.

6. Calculate the molecular formula.

EF Mass = (12.01 + 2.016 + 16.00) u = 30.03 u

The molecular formula is an integral multiple of the empirical formula.

MF = (EF)ₙ

$n = \dfrac{\text{MF Mass}}{\text{EF Mass }} = \dfrac{\text{150 u}}{\text{30.03 u}} = 5.00 \approx 5$

MF = (CH₂O)₅ = C₅H₁₀O₅

The molecular formula of X is C₅H₁₀O₅.

8 0

3 years ago

Convert 23.92inHg to torr.

White raven [17]

<h3><u>Answer;</u> </h3>

= 607.568 Torr

<h3><u>Explanation; </u></h3>

1 in of mercury is equivalent to 25.4 Torr

Therefore;

23.92 InHg will be equal to;

23.92 × 25.4

<u>= 607.568 Torr</u>

7 0

3 years ago