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worty [1.4K]
3 years ago
6

Which of the following describes a study that is “longitudinal”?

Chemistry
1 answer:
jolli1 [7]3 years ago
7 0

Answer:

A longitudinal study is a observational study that follows the same subjects repeatedly over a period of time, in some cases from birth to death

or

the same adults are tested at each time point: 20, 30, and 40 years of age

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Government should use informed science to help make policies protect all citizens<br> True or False
Sloan [31]

Answer:

yes

Explanation:

8 0
3 years ago
The compound known as diethyl ether, commonly referred to as ether, contains carbon, hydrogen, and oxygen. A 1.376 g sample of e
hoa [83]

Answer:

The answer to your question is: C₄H₁₀O

Explanation:

Data

          CxHyOz

mass sample : 1.376 g

mass CO₂ = 3.268 g

mass H₂O = 1.672 g

Process

Reaction

                      CxHyOz  + O₂ ⇒   CO₂  +  H₂O

1.- Calculate the moles and mass of carbon

Molecular mass CO₂ = 44g

                      44 g of CO₂ --------------  12 g of C

                      3.268 g of CO₂  --------    x

                         x = (3.268 x 12) / 44

                        x = 0.891 g of Carbon

                       12 g of carbon -----------  1 mol

                       0.891 g of C     ----------   x

                       x = (0.891 x 1) / 12

                       x = 0.0743 moles of carbon

2.- Calculate the moles and mass of hydrogen

                      18 g of water --------------- 2 g of H

                      1.672 g of H₂O ------------  x

                      x = (1.672 x 2) / 18

                      x = 0.186 g of hydrogen

                      1 g of hydrogen ------------  1 mol of H

                      0.186 g of H       ------------  x

                      x = (0.186 x 1) / 1

                      x = 0.186 moles of H

3.- Calculate the mass of Oxygen and its moles

Mass of Oxygen = 1.376 - 0.891 - 0.186

                           = 0.299 g of O₂

Moles of Oxygen

                             16 g of Oxygen ---------------- 1 mol

                             0.299 g of O    -----------------  x

                             x = (0.299 x 1) / 16

                             x = 0.019 moles of Oxygen

4.- Divide by the lowest number of moles

Carbon         0.0743/ 0.019 = 3.9 ≈ 4.0

Hydrogen     0.186/ 0.019 = 9.7 = 10

Oxygen         0.019/ 0.019 = 1

5.- Write the empirical formula

                              C₄H₁₀O                  

4 0
3 years ago
The transfer of energy by waves is also known as _______
Verdich [7]

Answer:

wave

Explanation:

'Wave' is a common term for a number of different ways in which energy is transferred: In electromagnetic waves, energy is transferred through vibrations of electric and magnetic fields.

i hope this helps and your welcom

5 0
3 years ago
Kenya has a pile of salt on the counter. She uses a pinch of it for a meal. Which of the following physical properties of the sa
AlladinOne [14]
The following choices are all extensive properties, meaning they do not change with the amount of the substance. Although, 3 of the properties, namely, density, solubility and thermal conductivity are temperature-dependent. Since the problem did not mention of heating, let's assume Kenya just used it directly for her meal. Among the choices, I think shape would change. Once you place it in the meal, you can no longer pinpoint the salt because it's shape has been changed.
7 0
3 years ago
Read 2 more answers
________ properties depend on the amount of material present.
Kamila [148]

Answer: Extensive!

Explanation:

6 0
3 years ago
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