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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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Determine which of the following statements is true:
alukav5142 [94]

Answer:

A. When an anhydrous salt becomes hydrated, it can change color.

Explanation:

The cobalt (II) chloride (CoCl₂) have a blue color in the anhydrous form while after hydration, most commonly it will form the hexahydrate, it will change its color to violet.

B. not really, if we take the cobalt (II) chloride in the anhydrous form the bond between cobalt and the chloride it is ionic.

C. nope, the mass is changed depending on the lost water mass

D. no, the mass will increase and sometimes as in the case of cobalt (II) chloride the color will change, so you have changes of the physical properties of the substance.

3 0
3 years ago
Why feo is basic oxide​
MAXImum [283]

Answer:

A basic oxide is an oxide which when combined with water gives off a base. When a substance reacts chemically, both as a base or acid it termed as an amphoteric solution. Neutral Oxide is one which neither has an acidic characteristic or a basic one. Metal Oxides have an oxidation number of -2 and generally comprise of an oxygen anion.

3 0
2 years ago
What happens to the pressure of a gas if the temperature is decreased
velikii [3]
The pressure of that gas will decrease..
5 0
3 years ago
Calculate the density of ammonia if 8.9 L of the gas weighs 6.86g
Greeley [361]
Answer: 2.3g

mark brainliest pls !!
5 0
1 year ago
Read 2 more answers
Consider the following four titrations: i. 100.0 mL of 0.10 M HCl titrated with 0.10 M NaOH ii. 100.0 mL of 0.10 M NaOH titrated
Olegator [25]

Answer:

Solution III < Solution II < Solution I < Solution IV

Explanation:

I) HCl + NaOH \longrightarrow H_2O + NaCl

Due to the rate of neutralization is 1 mol of NaOH with 1 mol of HCl and that we have equal volumes of both solution with the same concentration, they neutralize each other leaving a neutral pH (pH=7). Althought, because your titrating agent is a base the equivalence point will be a bit alkaline.  

II) The same as the point I) but now the titrating agent is the acid, the equivalence point will be neutral trending a bit to acid.  

III) Given that we have one strong acid neutralizing a weak base solution, in the equivalence point the the pH will be acid because the HCl (strong) dissociates compleately so we will have the 0.01 mol (100 ml of 0.1 M) of HCl with 0.01 mol>CH3NH2 (because is a weak base). How much less than 0.01 mol we have? <u>It depends of the strengh of the base and the pH will also depend on that</u>.

IV) This case is similar to the last one but with a strong base and a weak acid. So with a similar deduction the pH in the equivalence point will be alkaline (pH>7). How much? It depends on the strengh of the acid.

<u>In order of increasing pH: </u>

Solution III < Solution II < Solution I < Solution IV

3 0
3 years ago
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