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2 years ago

How many significant figures are in 0.00120

Chemistry

1 answer:

Svetllana [295]2 years ago

4 0

There are 3 significant figures

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PLEASE ANSWER

lyudmila [28]

Answer:

4 hours

Explanation:

7 0

3 years ago

Read 2 more answers

Which of the following would a chemist be most likely to study? A. what happens when a moving car comes to a stop B. what happen

Liono4ka [1.6K]

Answer:

B. what happens when iron rusts in the presence of water

Explanation:

7 0

3 years ago

When 1.2383 g of an organic iron compound containing Fe, C, H, and O was burned in O2, 2.3162 g of CO2 and 0.66285 g of H2O were

uysha [10]

Answer:

$\boxed{\text{C$_{15}$H$_{21}$FeO$_{6}$}}$

Explanation:

Let's call the unknown compound X.

1. Calculate the mass of each element in 1.23383 g of X.

(a) Mass of C

$\text{Mass of C} = \text{2.3162 g } \text{CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{0.632 07 g C}$

(b) Mass of H

$\text{Mass of H} = \text{0.66285 g }\text{H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g } \text{{H$_{2}$O}}} = \text{0.074 157 g H}$

(c)Mass of Fe

(i)In 0.4131g of X

$\text{Mass of Fe} = \text{0.093 33 g Fe$_{2}$O$_{3}$}\times \dfrac{\text{111.69 g Fe}}{\text{159.69 g g Fe$_{2}$O$_{3}$}} = \text{0.065 277 g Fe}$

(ii) In 1.2383 g of X

$\text{Mass of Fe} = \text{0.065277 g Fe}\times \dfrac{1.2383}{0.4131} = \text{0.195 67 g Fe}$

(d)Mass of O

Mass of O = 1.2383 - 0.632 07 - 0.074 157 - 0.195 67 = 0.336 40 g

2. Calculate the moles of each element

$\text{Moles of C = 0.63207 g C}\times\dfrac{\text{1 mol C}}{\text{12.01 g C }} = \text{0.052 629 mol C}\\\\\text{Moles of H = 0.074157 g H} \times \dfrac{\text{1 mol H}}{\text{1.008 g H}} = \text{0.073 568 mol H}\\\\\text{Moles of Fe = 0.195 67 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.845 g Fe}} = \text{0.003 5038 mol Fe}\\\\\text{Moles of O = 0.336 40} \times \dfrac{\text{1 mol O}}{\text{16.00 g O}} = \text{0.021 025 mol O}$

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

$\text{C: } \dfrac{0.052629}{0.003 5038}= 15.021\\\\\text{H: } \dfrac{0.073568}{0.003 5038} = 20.997\\\\\text{Fe: } \dfrac{0.003 5038}{0.003 5038} = 1\\\\\text{O: } \dfrac{0.021025}{0.003 5038} = 6.0006$

4. Round the ratios to the nearest integer

C:H:O:Fe = 15:21:1:6

5. Write the empirical formula

$\text{The empirical formula is } \boxed{\textbf{C$_{15}$H$_{21}$FeO$_{6}$}}$

5 0

3 years ago

Ter the symbol for the isotope used in blood flow analyses.

blondinia [14]

Answer:

The symbol of isotopes used for blood flow analysis is $\begin{array}{c}{141} \\ {58}\end{array} C e.$

<u>Explanation: </u>

Isotopes are the substances that exhibit the same atomic number but has a different mass number of an element.
The atomic number explains the number of protons present in the element and mass number explains the number of neutrons available in the element.
For blood flow analysis, the isotope element is cerium-141 and it is used in the chemical examination of blood flow particles.
Symbol used for this isotope is $\begin{array}{c}{141} \\ {58}\end{array} C e$ , where 141 indicates the amount of mass present and 58 indicates the proton number and 83 indicates neutron number present in that element.
The amount of mass in an atom is calculated by the sum of protons and neutrons present in it. Thus mass of isotope is 141 obtained by the sum of 58 protons and 83 neutrons present in that isotope.

8 0

3 years ago

What are five key accomplishments of Marie Curie?

shusha [124]

Her discovery of radium and polonium.

She was the first woman to win a nobel prize and a second one as well!

Marie Curie was the first women to be appointed as the director of the physics lab at Sorbonne.

She was also the first woman to become a professor at the University of Paris.

She helped make radiology units which were again portable and those assisted the field surgeons during the war.

Hope this helps :))

5 0

2 years ago