In the image above the ruler is measuring in centimeters. The blue cylinder falls somewhere between 2.7cm and 2.8cm according to the ruler. Since we can estimate the last digit I would say that the length of the cylinder is 2.76cm. Since I am estimating any number 2.72cm or 2.78cm could also be correct.

Why would 2.755 not be a correct measurement according to estimating the last digit?

Answer:

Explanation:

Given:

Amount in calories = 450 calories

Amount in joules = 3.5 × 100 joules

Find:

Computation:

We know that,

1 calories = 4.184 joules

So,

Amount in calories = 450 calories

= 450 × 4.184

= 1,882.8 joules

Amount in joules = 3.5 × 100 joules

=  [3.5 × 100] / 4.184

= 83.652 calories

Answer:

Quick you said:

-Purpose/Question

Ask a question.

-Research

Conduct background research. Write down your sources so you can cite your references. In the modern era, a lot of your research may be conducted online. Scroll to the bottom of articles to check the references. Even if you can't access the full text of a published article, you can usually view the abstract to see the summary of other experiments. Interview experts on a topic. The more you know about a subject, the easier it will be to conduct your investigation.

-Hypothesis

Propose a hypothesis. This is a sort of educated guess about what you expect. It is a statement used to predict the outcome of an experiment. Usually, a hypothesis is written in terms of cause and effect. Alternatively, it may describe the relationship between two phenomena. One type of hypothesis is the null hypothesis or the no-difference hypothesis. This is an easy type of hypothesis to test because it assumes changing a variable will have no effect on the outcome. In reality, you probably expect a change but rejecting a hypothesis may be more useful than accepting one.

-Experiment

Design and perform an experiment to test your hypothesis. An experiment has an independent and dependent variable. You change or control the independent variable and record the effect it has on the dependent variable. It's important to change only one variable for an experiment rather than try to combine the effects of variables in an experiment. For example, if you want to test the effects of light intensity and fertilizer concentration on the growth rate of a plant, you're really looking at two separate experiments.

-Data/Analysis

Record observations and analyze the meaning of the data. Often, you'll prepare a table or graph of the data. Don't throw out data points you think are bad or that don't support your predictions. Some of the most incredible discoveries in science were made because the data looked wrong! Once you have the data, you may need to perform a mathematical analysis to support or refute your hypothesis.

-Conclusion

Conclude whether to accept or reject your hypothesis. There is no right or wrong outcome to an experiment, so either result is fine. Accepting a hypothesis does not necessarily mean it's correct! Sometimes repeating an experiment may give a different result. In other cases, a hypothesis may predict an outcome, yet you might draw an incorrect conclusion. Communicate your results. The results may be compiled into a lab report or formally submitted as a paper. Whether you accept or reject the hypothesis, you likely learned something about the subject and may wish to revise the original hypothesis or form a new one for a future experiment.

Answer:

d

Explanation:

Answer:

(ii) Ethane and Heptadecane

Explanation:

The separation of all the species listed in the answer options for the question depends on the molar mass of each specie.

Ethane is a low molecular mass gas. It exists in the gaseous state at room temperature. However, heptadecane appears as a liquid because it has a greater relative molecular mass.

It is very easily to distinguish between the gas, ethane and the liquid heptadecane which is a high molecular mass alkane, hence the answer.

Answer:

≈ 0.104 liters  

Explanation:

We can use Boyle's Law: [tex]P_{1}V_{1} = P_{2}V_{2}[/tex]

P₁ = 2.50 atm

V₁ = 25.0 mL

P₂ = 457 mmHg

V₂ = ?

Because pressure should be in atm we will convert 457 mmHg to units in atm:

1 atm = 760mmHg so we can divide 457 by 760 and we get ≈ 0.601atm

Next we can plug in the units to the equation for Boyle's Law:

(2.50)(25.0) = (0.601)(V₂)

Solve for V₂

V₂ will give you ≈ 104mL or 0.104L

Either is correct depending on which unit they are asking you to use

Answer:

So, sodium oxide + water = sodium hydroxide + hydrogen is written Na2O+H2O-->NaOH+H.

To balance the equation it should read NaO+H2O-->2NaOH

Explanation:

Na2O+H2O-->2NaOH+0H2.......the 0H2 is dropped because there is no value

The correct balance of equation will be

Na2O + H2O - - > 2NaOH

A chemical equation where the number of atoms on both the reactant side and the product side of the reaction are equal is called a balanced chemical equation.

In a balanced chemical equation, not only the number of atoms but the charge and the mass is the same on both sides of the equation.

A chemical equation needs to be balanced to validate the law of conservation of mass. The law of conservation of mass states that the 'mass can neither be created nor destroyed in a chemical reaction'.

If the chemical equation is not balanced, it will go against the fundamental law of law of conservation of mass.

Thus, the chemical equations need to be balanced.

Therefore to balanced the given chemical equation, we equate the number of atoms on both the reactant and the product side of the reaction.

It will be written as

Na2O + H2O - - > 2NaOH

Read more about balanced chemical equations, here

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Answer:

inter atomic bonds

Explanation:

because it is loosely held

Answer:

This is because mechanical phase-separation device such as filtration, centrifugation etc operate according to the unique particle size feature in which they are designed to separates.

The process of centrifugation separates particles of size range between 0.1 μm to 5.0 μm efficiently.

The process of filtration however varies as there are different types of pore sizes which covers a wide range of particle sizes.

the molar concentration should be atleast 5mL off the solution since its disolved

Answer:

8.3

Explanation:

Convert mL to L.

12 mL×1 L1000 mL=0.012 L

Solve for molarity.

Molarity=moles of solute

liters of solution=0.10 mol0.012 L=8.3 M

Answer:

32

Explanation:

The vapour density of a gas is the number of times a given volume of gas or vapour is as heavy as the same volume of hydrogen at a particular temperature and pressure.

Vapour density = 2 × relative molecular mass of the gas or vapour

Relative molecular mass of SO2 = 32 + 2(16) = 64

Hence;

Vapour density of SO2 = 64/2

Vapour density of SO2 = 32

Answer:

Calcium: Alkaline Earth

Sodium: Alkali Metal

Hope it helps!

Answer:

Calcium is in Alkaline Earth

Sodium is in Alkali Metal

Answer: 0.01 moles (I am guessing)

Explanation:

Firstly, cm3 and ml are equal to one another, therefore 250cm3 can also be written as 250 ml. I Googled and found that ideally, one mole of gas will occupy a volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.

Answer:here is it...

Explanation:

The question tag for the statement "Lynne speaks French and German" would be "doesn't she?"

The question tag is a short question added to the end of a statement to turn it into a question and seek confirmation or agreement. It is usually formed by using an auxiliary verb opposite in polarity to the main verb in the statement.

In the given statement, "Lynne speaks French and German," the main verb is "speaks." Since the main verb is in the affirmative form, the question tag should use the negative form.

Therefore, we use the auxiliary verb "doesn't" (the negative form of "does") and add the pronoun "she" to match the subject of the statement.

Know more about question tag:

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Answer:

Carbon dioxide extinguishes work by displacing oxygen, or taking away the oxygen element of the fire triangle. The carbon dioxide is also very cold as it comes out of the extinguisher, so it cools the fuel as well.

Answer:

ipotseeeeeeeeeeeeeeee

Answer:

Hi there!!!

The answer is given in picture.

In question we had 2 sodium(Na) and chlorine (cl) but after reaction nacl donot contain it. so, we need to put 2 infront of nacl to make them equal.

As balancing chemical equation refers to the process of keeping or making equal to the atoms of both product and reactant.

Hope it helps..

Answer:

Explanation:

a )

Zn = Zn²⁺ + 2e   ( oxidation reaction )

Fe³⁺ + 3e = Fe( s ) ( reduction reaction )

b )

[ Zn = Zn²⁺ + 2e ] x 3

[ Fe³⁺ + 3e = Fe( s ) ] x 2

-------------------------------------------------------------------

3 Zn + 2 Fe³⁺ + 6e = 3 Zn²⁺ + 2 Fe ( s ) + 6e

3 Zn + 2 Fe³⁺  = 3 Zn²⁺ + 2 Fe ( s )

Answer:

physical

Explanation:

The change is physical.

A physical change involves a reversible change to the physical properties of substances, whereas a chemical change involves an irreversible change to the chemical properties of substances through a chemical reaction.

The dissolution of common salt is a physical change because the common salt can be retrieved by evaporating off the water. This is what was manifested by the deposition of common salt crystals on the wick.

Answer:

The dots were not properly located and arrows are not used in Lewis structures

Explanation:

If we intend to write a Lewis structure for a compound, that lewis structure must consist of only dots. These dots actually show the valence electrons on the outermost shell of the molecule.

We do not involve arrows when writing dot electron structures for compounds. The valence electrons of magnesium ought not to be written together because they are not a lone pair, rather they are two unpaired electrons. The use of an arrow suggests a coordinate covalent bond which is not the case here.

The correct lewis structure for MgCl2 is shown in the image attached to this answer.

Answer: B is the answer took the test

Explanation: both electrons of Mg should be transferred to one O atom...

Answer:

D. A combustion reaction

Explanation:

Answer:

has two double C-C bonds

Explanation:

A saturated compound is a compound having the full complement of hydrogen atoms for every carbon atom while an unsaturated compound does not contain the full complement of hydrogen atoms for every atom of carbon.

If we look at C3H4, the only possible structure of the compound is H2C=C=CH2. We can see from this arrangement that the compound contains a cumulative double bond. This is the specific structure that fits into one of the descriptions in the options, the compound contains two double bonds.

Answer:

The answer is "2.78".

Explanation:

Given values:

CD= 0.44

Formula:

[tex]\bold{f_r= \frac{v^{2}}{ g(s-1)D}}[/tex]

g=9.8

s= 2.7

D= 0.06

[tex]\to f_r=\frac{2.5^2}{9.8(2.7-1)0.06}\\\\[/tex]

        [tex]=\frac{2.5 \times 2.5}{9.8 \times 1.7 \times 0.06 }\\\\=\frac{6.25}{.9996 }\\\\=6.252501[/tex]

[tex]\phi = \frac{82\times v}{ \sqrt{cD} \times f_r^{-1.5}}\\\\[/tex]

   [tex]= \frac{82 \times 0.25 }{ \sqrt{0.44} \times 6.25^{1.5}}\\\\=2.4285\\[/tex]

[tex]\frac{\bigtriangleup P f_1 s_1}{L} = \frac{\bigtriangleup Pf_w}{L}(1+\phi)\\[/tex]

           [tex]=\frac{2fwSwv^2 (1+2.4285)}{D}\\\\[/tex]

[tex]Re= \frac{D \bar v Sw}{M_w}\\[/tex]

     [tex]=\frac{0.06 \times 2.5 \times 1000 }{0.001}\\\\=\frac{150 }{0.001}\\\\= 150 \times 10^{3}\\\\= 1.50 \times 10^{5}\\\\[/tex]

[tex]fw= 0.00389[/tex]

[tex]\to \frac{\bigtriangleup P f_1 s_1}{L}[/tex]

[tex]\to \frac{2 \times 0.00389 \times 1000 \times2.5^2 \times 3.4265}{0.06}\\\\\to 2.78[/tex]

Answer:

Objetos elásticos: forma de cama y neumático de ciclo.

Objetos no elásticos: muebles y cuchara

Explicación:

Dos materiales elásticos que están presentes en las casas son forma y neumático de ciclo y dos materiales no elásticos como muebles y cuchara. Los materiales elásticos son aquellos que muestran alguna deformación en su forma al aplicar fuerza y al eliminar la fuerza, recupera su forma original, mientras que los materiales no elásticos son duros y no pueden cambiar su tamaño y forma.

Answer:

1.65485688 × 10121 grams

Explanation:

Aside from those discrete items, anything like rice or flour can be measured out to make up 100 grams. For example, 1/2 cup (125 ml or about 4 and 1/2 fl. oz) of dry rice weighs very close to 100 grams.

Answer:

a formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.

Hope this helped!!!

Answer:

Empirical formulas show the simplest whole-number ratio of atoms in a compound

Explanation:

Answer:

b

Explanation:

the eye is the most important so it would grow but it will take some time because if we plant it with piece it has some food

This means that in 100g of solution, there are 5g of HCl and 95g of water

Answer:

• pH = 3.0

• pH = 2.70

• pH = 3.61

• pH = 8.28

• pH = 1.40

Explanation:

El pH es una medida en química usada para determinar el grado de acidez o basicidad en una solución.

Se define como:

pH = -log₁₀ [H⁺]

El - logaritmo de la concentración molar de H⁺

Para las concentraciones de H⁺ dadas:

• [H+] = 0.001 M

pH = -log (0.001M) = 3

pH = 3.0

• [H+] = 0.002 M

pH = -log (0.002M)

pH = 2.70

• [H+] = 2.45X10-4 M

pH = -log (2.45X10-4 M )

pH = 3.61

• [H+] = 5.2X10-9 M

pH = -log (5.2X10-9 M)

pH = 8.28

• [H+] = 0.04 M

pH = -log (0.04M)

pH = 1.40

Answer:

According to the definitions given, atomic mass which is also called atomic weight is the measured total mass of an element's atom. Whereas, atomic number is nothing but the total number of neutrons and protons in the nucleus of an atom....

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