Why is elemental zinc considered a pure substance?
Select one:
It is a metal.
It is a mixture of different atoms.
All elements are considered pure substances.
It must be created in a lab.

Answer:

What is the name of the lab tool that is used to transfer a sample to a microscope slide?

A-a dropper

C-scissors

D-a ruler

Explanation:

got it wrong but this is the answer edg 2021

In the preparation of a microscopic slide, the items which are used are medicine dropper, scissors, and a slip cover. Thus, the correct option is D.

Microscope slides are made for the purpose of observations of different objects. After the observation, the slides are discarded. In most cases, the slides use a liquid mounting medium such as water or glycerin.

The procedure for the preparation of the slide is as follows:

1. Place a drop of liquid mounting medium in the center of the slide.

2. Position the sample on liquid with the use of tweezers.

3. At an angle, place one side of the cover slip against the microscopic slide making contact with outer edge of the liquid drop.

4. Lower the cover slip slowly, avoiding air bubbles.

5. Remove the excess water present in it with the help of paper towel.

Therefore, the correct option is D.

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Answer:

These three points all lie on the same line. This line could be called 'Line AB', 'Line BA', 'Line AC', 'Line CA', 'Line BC', or 'LineCB' .

Answer:

A. 7.56

b. 57.12

Explanation:

Hope that's right have a nice day :)

Answer:

the compound formed between nitrogen and magnesium is Magnesium Nitride

Answer:

Answers. 7.8286×10²¹ particles.

Explanation:

The particles present in the sample of ammonium carbonate are  [tex]0.7826*10^{23}[/tex] particles. This can be calculated by using number of moles.

It is defined as the given mass over molar mass.

Given mass= 12.7 g

Molar mass of ammonium carbonate= 96.06 g/mol

Number of moles = 12.7 g / 96.06 g/mol

Number of moles = 0.13 moles

One mole:

A mole is the amount (10) of material containing [tex]6.02214 * 10^{23}[/tex] particles.

1 mol =  [tex]6.02214 * 10^{23}[/tex] particles

So, 0.13 moles = [tex]6.02214*10^{23}*0.13=0.7826*10^{23} \text{ particles}[/tex]

thus, there are [tex]0.7826*10^{23}[/tex] particles are present in 12.7 g of ammonium carbonate.

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Answer:

I believe it is 5 N to the right

Explanation:

Answer:

mass number- 7 (round it to 7

Explanation:

Answer:

Organisms can be classified into one of three domains based on differences in the sequences of nucleotides in the cell's ribosomal RNAs (rRNA), the cell's membrane lipid structure, and its sensitivity to antibiotics. 3. The three domains are the Archaea, the Bacteria, and the Eukarya.

Explanation:

Answer:

bro

Explanation:

If the product of the reaction is analyzed and found to contain 0.130 g of nitrogen and 0.370 g of oxygen are N2O5

Answer:

This question is incomplete

Explanation:

This question is incomplete because of the absence of the illustration (diagram or figure). However, general understanding of the bone cells can help answer the question.

Bone cells come together to form a connective tissue called bone. The bone is a connective tissue that contains cells and other substances. The bone assists in the storage of minerals, providing of support to the body, protecting internal organs and providing attachment for muscles and tendons. The bone can be either compact or spongy (cancellous). The spongy bone is lighter and less dense than the compact bone. The bone is primarily composed of a mineral called hydroxyapatite (made of calcium and phosphorus) but also contains other minerals (such as magnesium and sodium). Hence, the bone cells are also expected to have high concentration of the minerals of hydroxyapatite (calcium and phosphorus).

The bone cells cannot however comprise a combination of nervous and muscular tissue because a cell is the structural unit of life and cannot as such comprise of a higher structure. Thus, options A, B and C are correct.

Since the rightward force is greater than the leftward force by a magnitude of 10 Newton, the ball will: A. move to the left.

Given the following data:

A net force can be defined as the vector sum of all the forces acting on an object.

Hence, net force is the sum of all forces acting simultaneously on an object.

To determine the direction in which the ball would move if the four forces shown are applied at the same time:

For the downward and upward force:

[tex]Net\;force = 50-50\\\\Net\;force = 0\;Newton[/tex]

For the rightward and leftward force:

[tex]Net\;force = 40-30\\\\Net\;force = 10\;Newton[/tex]

Since the rightward force is greater than the leftward force by a magnitude of 10 Newton, the ball will move to the left.

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The question is incomplete, the complete question is;

AlBr3 can be used as a catalyst in the Friedel-Crafts alkylation reaction. The correct name for the compound represented by the formula AlBr3 is —

aluminum bromide

monoaluminum tribromide

aluminide bromine

aluminum tribromide

Answer:

aluminum bromide

Explanation:

Having known that AlBr3 is an ionic compound and aluminium is the central atom here, we now have to ask ourselves if Aluminium exists in other stable oxidation states.

We must take cognizance of the fact that the oxidation number of the central atom in a compound becomes part of the name of that compound when other stable oxidation states for atoms of the same elements exists.

Since the +3 state is the only stable oxidation state for aluminium, the name of the compound is simply aluminium bromide.

The number of Na atoms in the reactants = 2

Every chemical reaction involves compounds that can act as reactants or products

The reactants will react to produce products

The reactants are usually written on the left side of the reaction, while the products on the right side of the reaction

Reaction

2 NaCl + H₂SO₄ → 2 HCl + Na₂SO₄

The element with atomic number 11  = Na(Natrium)

The number of atoms of the element that reacts or is produced can be seen from the reaction coefficient and the number of atoms in the compound

Na in NaCl = 1 atom

From equation, cofficient for NaCl = 2, so number of atoms of Na=2 x 1 = 2

Answer:

Glass A has a greater mass than glass B

Answer:

Glass A has a greater mass than Glass B

hope this helped :>

Answer:

25

Explantion:

atomic no. =  no. of eletron

Answer:

K potassium have least ionization energy among these four

Explanation:

Ionization energy values are given in kilo joule per mole

Ca 590

Ge 762

K 419

Ga 579

From above data we can understand stand K has least and Ge has highest ionization energy

Moles of O₂ = 3.92

Given

V=1 L

T=-118 °C + 273 = 155 K

P = 49.77 atm

Required

moles of O₂

Solution

the gas equation can be written  

[tex]\large {\boxed {\bold {PV = nRT}}}[/tex]

where  

P = pressure, atm  

V = volume, liter  

n = number of moles  

R = gas constant = 0.08206 L.atm / mol K  

T = temperature, Kelvin  

Input the value :

n= PV/RT

[tex]\tt n=\dfrac{49.77~atm\times 1~L}{0.082\times 155}=3.92~moles[/tex]

Answer:

B. Potassium Sulfate

Explanation:

SO4=sulfate

-2 charge cancels

Answer:

B. Potassium Sulfate

Explanation: for clever users /plato

Answer:

Na2O2

the formula of sodium peroxide

Answer:

ionic bond

Explanation:

cation calcium looses 2 electrons to bond with two iodine atoms to form CaI2 (Calcium Iodide)

Answer:

Sulfur (in British English: sulphur) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur

Answer:

Next, the lb will be canceled at 2.2 lb and the kg would be canceled at 1 kg. You cross, multiply, then. 46 x 1 x 1000 is 46000, only moving to the decimal point. 1 x 2.2 x 1 will stay the same, so you'd have 46000 over 2.2.

Explanation:

kuroo man <3

Answer:

Next, the lb will be canceled at 2.2 lb and the kg would be canceled at 1 kg. You cross, multiply, then. 46 x 1 x 1000 is 46000, only moving to the decimal point. 1 x 2.2 x 1 will stay the same, so you'd have 46000 over 2.2.

Explanation:

halo

Explanation:

calcium hypo chlorite

Ca(ClO)2

Explanation:

CA(CIO) IS RHE FORMULA FOR BLEACHING POWDER...

Answer:

We can no longer ignore the fact that the world's climate is becoming more unpredictable and more extreme. As water levels rise, the risk of flooding looms large. At the same time, periods of drought are becoming longer and more frequent. Yet, our most precious resource – our planet's biosphere – is not only under threat. It is also the source of many of our solutions. Green Climate Solutions is the Wageningen Environmental Research programme that applies our understanding of nature and natural processes to address the challenges of climate change.

Answer:

The peripheral nervous system can be further divided into the autonomic system, which regulates involuntary actions, and the somatic system, which controls voluntary actions.

Explanation:

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Answer: voluntary actions.

Explanation:The peripheral nervous system can be further divided into the autonomic system, which regulates involuntary actions, and the somatic system, which controls voluntary actions.

Answer:

O, Ca, Zn, Br

Sc, K, Br,

Explanation:

The correct order of the chemical elements from highest to lowest electronegativity is: C. Br, Zn, Sc, Ca, K.

Electronegativity refers to a measure of the ability of an atom of a chemical element to attract any shared pair of electrons.

Generally, the electronegativity of a chemical element typically increases across the period from left to right.

In Chemistry, the electronegativity of some of the chemical element are:

Hence, the order of the chemical elements from highest to lowest electronegativity is:

1. Bromine (Br) = 2.96

2. Zinc (Zn) = 1.65

3. Scandium (Sc) = 1.36

4. Calcium (Ca) = 1.0

5. Potassium (k) = 0.82

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Answer:

I think it's B

Explanation:

I took the exam

Answer:

36.28 kg

Explanation:

Given data:

Gravitational potential energy of object = 800 J

Height from ground = 2.245 m

Mass of object = ?

Solution:

Formula:

P.E = mgh

g =acceleration due to gravity =  9.8 m/s²

by putting values,

800 J = m× 9.8 m/s² ×2.25 m

J = kgm²/s²

800 kgm²/s² = m× 22.05 m²/s²

m = 800 kgm²/s² /22.05 m²/s²

m = 36.28 kg

Answer:

1 mole of Na = mass of 22.99 g, 1 mole of Si = mass of 28.09 g.

Answer:

0.001 mole of NaF.

Explanation:

From the question given above, the following data were obtained:

Volume of solution = 100 mL

Molarity = 0.01 M

Mole of NaF =?

Next, we shall convert 100 mL to litre (L). This can be obtained as follow:

1000 mL = 1 L

Therefore,

100 mL = 100 mL × 1 L / 1000 ml

100 mL = 0.1 L

Thus, 100 mL is equivalent to 0.1 L.

Finally, we shall determine the number of mole of NaF present in the solution. This can be obtained as follow:

Volume of solution = 0.1 L

Molarity = 0.01 M

Mole of NaF =?

Molarity =mole /Volume

0.01 = mole of NaF / 0.1

Cross multiply

Mole of NaF = 0.01 × 0.1

Mole of NaF = 0.001 mole.

Thus, 0.001 mole of NaF is present in 100 mL of the solution.