1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
exis [7]
3 years ago
5

50 POINTS: PLEASE ANSWER AS QUICK AS POSSIBLE!

Chemistry
2 answers:
Dvinal [7]3 years ago
6 0

Explanation:

The lack of a control group

____ [38]3 years ago
5 0
The answer would be “the lack of a control group.” To make the results more accurate, the scientists should have used a placebo group to use as a comparison.
You might be interested in
What is the mass in grams of 9.76 x 10 12 atoms of naturally occurring sodium?
Fiesta28 [93]
The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 × 10²³] (which is used as a standard in the world of moles).

Now,

          if     6.02 × 10²³ atoms are found in 1 mole ofsodium
   then let  9.76 × 10¹² atoms are found in     x

⇒     x  =    (9.76 × 10¹² )  ÷  (6.02 × 10²³)

            =  1.619 × 10⁻¹¹ mol


Now, mass = moles × molar mass

∴ mass of Na = 1.619 × 10⁻¹¹ mol ×  23 g/mol
                      = 3.72 × 10⁻¹⁰ g


4 0
3 years ago
An FAS calibration curve (absorbance, y-axis vs. FAS in g/mL) gave an equation he regression line of: y-3678(x)+0.056. If an unk
mezya [45]

Answer:

FAS concentration = 1.61*10^-4M

Explanation:

Beer Lambert's law relates the absorbance (A) of a substance to its concentration (c) as:

A = \epsilon lc----(1)

where ε = molar absorption coefficient

l = path length

A plot of 'A' vs 'c' gives a straight line with slope = εl

In addition absorbance (A) is related to % Transmittance (%T) as:

A = 2-log%T----(2)

For the FAS solution, the corresponding calibration fit is given as:

y = 3678(x) + 0.056

This implies that the slope = εl = 3678

It is given that %T = 25.6%

A = 2-log(25.6)=0.592

Based on equation(1):

c = \frac{A}{\epsilon l}=\frac{0.592}{3678}=1.61*10^{-4}M

8 0
3 years ago
25. The periodic table is based on an element's A. atomic number. B. molecular size. C. molecular mass. D. atomic mass.
VashaNatasha [74]
It is arranged by Atomic Number
8 0
3 years ago
Read 2 more answers
Which process is similar to binary fission?
elixir [45]
Fission is similar to mitosis because they both involve splitting. 

Answer: <span><span>d. mitosis</span></span>
8 0
3 years ago
Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?
Alexus [3.1K]
Given a mole each for iron and magnesium, the number of atoms of each element is equal. Iron has a greater mass due to its greater molecular weight. The correct statement among the choices is D.
6 0
3 years ago
Read 2 more answers
Other questions:
  • When calculating global population growth, the death rate is _____.
    14·2 answers
  • An element has a mass number of 9 and 5 neutrons. What element is it?
    11·2 answers
  • If a neutral atom has a mass of 12 amu and an atomic number of 5, determine the number of protons, neutrons, and electrons in th
    14·2 answers
  • Which best describes an element
    5·1 answer
  • What should the person do?
    10·1 answer
  • What simple machine is a leaf rake
    15·1 answer
  • Denmark is characterized as temperature as a region . the winters typicky experience frequent snowfall and low temperatures. in
    6·1 answer
  • BRAINLIESTT
    13·1 answer
  • Which state of matter has neutral particles that bounce off one another as they collide? A: Gas B: Liquid C: Plasma D: Solid ​
    15·2 answers
  • 9th grade...Chemistry help needed​
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!