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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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The length breadth and thickness of a brick is 18cm 8 cm and 5cm respictively find the area of the widest part of rhe brick​
Sunny_sXe [5.5K]

Answer:

144cm²

Explanation:

Given dimensions:

     Length x breadth x thickness

        18cm  x   8cm    x    5cm

The widest part of this figure will be the face containing the length and the breadth.

The breadth is the width of the figure;

Area of the widest part  = length x breadth = 18cm x 8cm  = 144cm

The area of the widest part of the figure is 144cm²

4 0
3 years ago
Now consider the reaction a+2b⇌c for which in the initial mixture qc=[c][a][b]2=387 is the reaction at equilibrium? if not, in w
Paul [167]
Solving this chemistry is a little bit hard because the question didn't give some important detailed. 
So first, there are a couple problems with your question. 
We will just need to know which direction will it proceed to reach equilibrium.
Your expression for Kc (and Qc ) for the reaction should be: 
Kc = [C] / [A] [B]^2 
You have not provided a value for Kc, so a value of Qc tells you absolutely nothing. Qc is only valuable in relation to a numerical value for Kc. If Qc = Kc, then the reaction is at equilibrium. If Q < K, the reaction will form more products to reach equilibrium, and if Q > Kc, the reaction will form more reactants.
5 0
3 years ago
A sample of hydrated copper (II) sulfate (CuSO4•nH2O) is heated to 150°C and produces 103.74 g anhydrous copper (II) sulfate and
wariber [46]

Answer:

5

Explanation:

Firstly, we convert what we have to percentage compositions.

There are two parts in the molecule, the sulphate part and the water part.

The percentage compositions is as follows:

Sulphate- (103.74)/(103.74 + 58.55) × 100% = apprx 64%

The water part = 100 - 64 = 36%

Now, we divide the percentages by the molar masses.

For the CuSO4 molar mass is 64 + 32 + 4(16) = 160g/mol

For the H2O = 2(1) + 16 = 18g/mol

Now we divide the percentages by these masses

Sulphate = 64/160 = 0.4

Water = 36/18 = 2

The ratio is thus 0.4:2 = 1:5

Hence, there are 5 water molecules.

3 0
3 years ago
Which compound is made from metals and non metals​
Grace [21]
It’s -> Ionic compound
3 0
3 years ago
Which will contain the greater number of moles of potassium ion: 30.0 ml of 0.15 m k2cro4 or 25.0 ml of 0.080 m k3po4?
Dahasolnce [82]
<span>30.0 ml of 0.15 m K2CrO4 solution will have more potassium ions. Let's see the relative number of potassium ions for each solution. Since all the measurements are the same, the real difference is the K2CrO4 will only have 2 potassium ions per molecule while the K3PO4 solution will have 3 potassium ions per molecule. K2CrO4 solution 30.0 * 0.15 * 2 = 9 K3PO4 solution 25.0 * 0.080 * 3 = 6 Since 9 is greater than 6, the K2CrO4 solution will have more potassium ions.</span>
3 0
3 years ago
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