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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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Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation. The reaction is C2H2(g)+2H2(g)?C2H6(g)
Alecsey [184]

Answer:

Keq =1.50108

Explanation:

The given reactionis

 C₂H₂(g) +2H₂(g) -------------> C₂H₂(g)

   ΔG0 f=ΔG0f n (products) - ΔG0f n (reactants )

              = -32.89 kJ/mol - (209.2 kJ/mol+2*0.0 kJ/mol)

              = - 242.09kJ/mol

   ΔG= -RTlnKeq

   ln Keq = -ΔG/RT

           =-(- 242.09kJ/mol ) / 2 k cal /mol*298 K

           =0.406

    Keq =e0.406

         Keq =1.50108

3 0
3 years ago
Read 2 more answers
What is hydrogen ion concentration of an acid solution whose PH is 3.4?​
meriva
It’s easy, if the PH of any acidic solution = -Log[H+], where [H+] is hydrogen ion concentration, multiply each term by (-1) then raise each term as a power to (10), so it will become like this:-
[H+] = 10^(-PH)
4 0
3 years ago
Describe, on a molecular level, how you would expect these lipids to behave in water.
Gelneren [198K]
Lipids are hydrophobic; They would be insoluble, group together, and float to the top
7 0
3 years ago
A certain solid has a density of 8.0 g/cm3. if 4.0 g of this solid are poured into 4.00 ml of water, which drawing below most cl
Alexandra [31]
Answer is: <span>the volume of water after the solid is added</span> is 4.5 ml.
d(gold) = 8.0 g/cm³; density of gold.
m(gold) = 4 g; mass of gold.
V(gold) = m(gold) ÷ d(gold); volume of gold.
V(gold) = 4 g ÷ 8 g/cm³.
V(gold) = 0.5 cm³ = 0.5 ml.
V(water) = 4.00 ml = 4.00 cm³.
V(flask) = V(gold) + V(water).
V(flask) = 0.5 cm³ + 4 cm³.V = 4.5 cm³.
4 0
3 years ago
Which of the following is the best example of chemical weathering?
shepuryov [24]

Answer: A. Limestone rocks dissolving in water

Explanation:

B: This is a physical change; it changes an object physically rather than chemically. It does not change the composition of the concrete, only the shape.

C: This is also a physical change because the water is just dragging sand with it, but not actually changing the composition of it.

D: Similar to option B, this is an example of physical weathering because the ice only divides the rock into different parts but doesn't change the composition or complexity of it.

4 0
3 years ago
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