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Tamiku [17]
4 years ago
11

Which best describes the purpose of a control sample

Chemistry
1 answer:
emmasim [6.3K]4 years ago
8 0

Answer:

A control group in a scientific experiment is a group separated from the rest of the experiment, where the independent variable being tested cannot influence the results. This isolates the independent variable's effects on the experiment and can help rule out alternative explanations of the experimental results.

Explanation:

hope this is what you need

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A compound has an empirical formula of AB and a molar mass of 90 g/mol. What is its
Lelu [443]

Answer:

A3B3

Explanation:

Molecular formula = n x empirical formula

(AB) n = 90

MM of AB = 30 g/mol

30n = 90

Divide both side by the coefficient n i.e 30

n = 90/30 = 3

Molecular formula = n x empirical formula

Molecular formula = n x (AB)

Molecular formula = 3(AB) = A3B3

8 0
3 years ago
MY ELEMENT IS SODIUM
garri49 [273]

Answer:

Explanation:

1. The element you selected is Sodium. some of the physical properties are

i. Sodium has a strong metallic lustre

ii. Sodium are usually silver white in color

iii. Sodium is soft it can be cut with knife

iv. Sodium are malleable and ductile.

v.  Sodium conduct electricity

Sodium belong to group 1 elements which are called Alkali metals. Sodium have one valency electron and it gives this electron easily during bonding . This is one reason sodium and other alkali metals are very reactive. Sodium can instantly be oxidized by water.  Sodium has a relative atomic mass of approximately 23 amu.

2. There are various models that describe atoms .This models includes John Dalton models, J.J Thompson model, Ernest Rutherford model, Bohr's models etc. This models made us understand the role and location of each sub atomic particles. The models shed more light on subatomic particles like electron which revolve around the nucleus.  It provide more information on what contribute to the weight of an atom.

3. The proton , neutron and electron are subatomic particles of an atom. The proton and the neutron are located at the nucleus of an atom.  The proton and neutron contributes majorly to the weight of an atom. The proton is positively charge while neutron has no charge.

Electron is found to move around the nucleus in cloud. The electron is negatively charge. The electron determines bonding of atoms. An atom is electrically neutral if the number of proton is equal to the number of electron.

4. The four fundamental forces includes weak nuclear forces , strong nuclear forces , gravity and electromagnetic forces.

Weak nuclear forces is responsible for particle decay .Nuclear forces don't play a role in chemical reaction . If they are involve in a reaction it becomes nuclear reaction not chemical reaction.

Strong nuclear forces causes a strong nuclear interaction and it is the strongest among the 4 fundamental forces. This strong force only operate when subatomic particles are much closer to each other.

Gravity force is too weak to affect chemical reaction much. The gravity forces involves the interaction between two objects with energy and mass.

The electromagnetic force act between charged particles like negatively charged electron and positively charged proton. Electromagnetic force is the most important force in chemical bonding as it depends on the arrangement of atoms and the state of their electron. Electromagnetic forces exist in various forms like the covalent bond, metallic, ionic , dipole dipole, hydrogen bonds and many more. The major force involve in chemical bonding is the electromagnetic force.

8 0
4 years ago
Plasmid DNA and a gene of interest are cut with the enzyme PpuMI. Write a possible sequence of bases for the sticky end of the g
nasty-shy [4]

Answer:

5' RG        GWCCY 3'

3' YCCWG        GR 5'

Explanation:

The enzyme PpuMI is a restriction endonuclease enzyme, it has a specific recognition site where it cut the DNA. The source of the enzyme is from ​​an E. coli strain that carries the PpuMI gene from Pseudomonas putida (R. Morgan).

The enzyme PpuMI recognizes specific sequence with palindrome arrangement. It target the sequence 5' RGGWCCY 3'

target Sequence: 5' RGGWCCY 3'

                            3' YCCWGGR 5'

The enzyme cleavage point is at:

5' RG^GWCCY 3'

3' YCCWG^GR 5'

The product of the cleavage will give a sticky end Cleavage:

5' RG        GWCCY 3'

3' YCCWG        GR 5'

Note: R stands for purines (adenine and guanine). Y stands for pyrimidines (cytosine, thymine, and uracil). And W represents adenine or thymine.

5 0
3 years ago
What are electron configurations?
sweet-ann [11.9K]

electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (e.g., a crystal).

3 0
3 years ago
out of the potential unknowns in this experiment, which one would be the best choice to create a buffer with a ph of 2.0?
ArbitrLikvidat [17]

For a buffer solution, pKa Equals the solution's pH. Choose a molecule with a pKa close to 2.0, such as sodium bisulfate,   in order to prepare pH = 2.0.

In order to create a buffer solution, a weak acid and salt, such as CH3COOH and CH3COONa, or a weak base, such as NH4OH and NH4Cl, are typically combined with salt. To understand how a buffer works, think about the example of a solution created by combining sodium acetate with acetic acid. Is called as buffer solution.

The sodium bisulfate salt of the anion has the chemical formula NaHSO4 and is often referred to as sodium bisulfate. An equivalent of sodium base, known as sodium bisulfate, is used to partially neutralize sulfuric acid.

Learn more about buffer solution here

brainly.com/question/24262133

#SPJ4

5 0
2 years ago
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