Answer:early models of telephones were used with a twirl of numbers
Explanation:
Not advanced technology
Answer:
Yes it is hard. For some of us. I already gave up, but now hes coming back. Id say sometimes its useless to get his attention if he never even pays attention to you anyways. It sucks because its so hard to get then to notice you for once.
Explanation:
The answer is 267.93 g
Molar mass of CaBr2 is the sum of atomic masses of Ca and Br:
Mr(CaBr2) = Ar(Ca) + 2Ar(Br)
Ar(Ca) = 40 g/mol
Ar(Br) = 79.9 g/mol
Mr(CaBr2) = 40 + 2 * 79.9 = 199.8 g/mol
The percentage of Br in CaBr2 is:
2Ar(Br) / Mr(CaBr2) * 100 = 2 * 79.9 / 199.8 * 100 = 79.98%
Now make a proportion:
x g in 79.98%
335 g in 100%
x : 79.98% = 335 g : 100%
x = 79.98% * 335 g : 100%
x = 267.93 g
Answer:
0.252 milimoles
Explanation:
To convert mass of a substance to moles it is necessary to use the molar mass of the substance.
The formula of morphine is C₁₇H₁₉NO₃, thus, its molar mass is:
C: 17*12.01g/mol = 204.17g/mol
H: 19*1.01g/mol = 19.19g/mol
N: 1*14g/mol = 14g/mol
O: 3*16g/mol = 48g/mol.
204.17 + 19.19 + 14 + 16 = <em>285.36g/mol</em>
Thus, moles of 71.891 mg = 0.071891g:
0.071891g × (1mol / 285.36g) = 2.5193x10⁻⁴ moles
As 1 mole = 1000 milimoles:
2.5193x10⁻⁴ moles = <em>0.252 milimoles</em>
The mass of solute per 100 mL of solution is abbreviated as (m/v). Mass is not technically the same thing as weight, but the abbreviation (w/v) is also common. 262 grams of sucrose are needed to make 655 mL of a 40.0% (w/v) sucrose solution
<h3>Define Solute</h3>
A solute is a material that dissolves in a solution. The amount of solvent present in fluid solutions is greater than the amount of solute. The two most common examples of solutions in daily life are salt and water. Salt is the solute because it dissolves in water.
<h3>forms of ratios for product concentration or yield:-</h3>
- w/v:- Weight by volume or weight per volume are the terms used. Any solid compound's concentration in a liquid can be calculated using it. It is measurable in gm/ml.
- Weight by weight ratio is referred to as w/w.It is employed to determine the final yield of the compound obtained from the starting compound. as in —mg/—gm.
It provides the real yield of the substance or item.
- Volume/volume. It is used to specify a liquid's composition or percent in a liquid compound.
using w/v we can calculate the weight of sucrose:-
40.0% means 40 g sucrose/ 100 g solution
40.0g sucrose x (655/100)=grams of sucrose
262 grams of sucrose are needed to make 655 mL of a 40.0% (w/v) sucrose solution.
Learn more about Solute here:-
brainly.com/question/14397121
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