A scientist has a sample of a substance that could be magnesium, sodium, stainless steel, or copper. Name two properties the scientist could use to identify the substance and explain why the scientist could use each property to identify the substance.

Answer:

Na²O (Sodium-oxide)

Explanation:

Physical state - Solid

Appearance - White solid

Solubility - Yes. Formes NaOH

Color - White

Nature - Basic

Answer:

Explanation:

Since mixtures are impure substances that do no combine chemically, they can be separated by physical means. Mixtures are best separated using the different separation techniques. Some of the techniques are filtration, decantation, distillation, e.t.c The separation techniques will restore different components of the mixture into their separate phases and composition.

Answer:

It’s Replication

Explanation:

If someone conducts an experiment which is done once already at the same conditions and criterias, it can be said as replicating the experiment. Hence, this is an example of replication of the experiment.

Replication is the act of repeating an experimental setup in order to gauge the phenomenon variability. As defined by ASTM in standard E1847, replication is "the repetition of the entire set of the experimental treatment combinations to be compared. A replicate is one of the repeats."

Repeated measurements of the same item are not the same as replication since they are handled differently in statistical experimental design and data processing.

Single-item testing or evaluation may not be representative of a batch or process and does not account for item-to-item variation. Therefore, repeating the same experiment to test the productivity of the results of an experiment is called replication.

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Is this supposed to be a question or something??? if so i need context.

Wood burning, particularly for home heating, involves the combustion of wood to release thermal energy. Modern techniques, such as the use of efficient wood stoves, aim to reduce the environmental impact by cutting down on pollutants. The sustainability of wood as a fuel largely depends on the sourcing and management of the harvested wood.

The process of wood burning in fireplaces or for home heating is an application of combustion, wherein wood is used as a biomass fuel. This process converts the carbon in wood into carbon dioxide and releases a significant amount of thermal energy. Modern home heating methods, such as high-efficiency wood stoves or fireplace inserts, have been developed to burn wood more efficiently than traditional open fireplaces. These advanced heating systems are designed to minimize pollutant emissions, such as carbon monoxide and particulate matter, making them a cleaner alternative to fossil fuels.

However, the sustainability of using wood as a fuel depends heavily on the source of the wood. If harvested from managed forests or urban trees that necessarily need to be removed, it can be a renewable resource. But, the indiscriminate cutting of wood, particularly in undeveloped countries for cooking and heating, can lead to deforestation and negatively impact ecosystems.

Answer:

a) 2 significant figures

b) 5 significant figures

c) 5 significant figures

d) 1 significant figures

Explanation:

• All non-zero digits are significant.

E.g. - 421 has 3 significant figures.

• Zeros between non-zero digits are significant.

E.g. - 502 has 3 significant figures.

• In a decimal less than 1, all zeros to the left of non-zero digits are not significant.

E.g. - 0.0345 has 3 significant figures.

Answer:

8

Explanation:

because 14-6 is 8

Answer:

S is the limiting reagent.

Explanation:

To find the limiting reactant we must first write the balanced chemical reaction. It must be correctly balanced so that we can find the proper mole ratios.

2 S (s) + 3 O2 (g) + 4 NaOH (aq) → 2 Na2SO4 (aq) + 2 H2O (l)

After this we will convert our measurements to moles. For mass we do this by dividing by the molar mass.

2g ÷ 32.06 = 0.06238mol S

3g ÷ 32.00 = 0.09375mol O₂

Now that we have the moles of each of the reactants, we can multiply them by their mole ratio with a reactant.

0.06238mol S × 2/2 = 0.06238mol H2O

0.09375mol O₂ × 2/3 = 0.06250mol H2O

S is our limiting reagent because it makes the smaller amount of moles.

The term used to denote randomness is entropy, the correct option is C.

The entropy of an object is a measure of the amount of energy that cannot be used to perform work.

Entropy is also a measure of the number of possible configurations for atoms in a system. Entropy is a measure of uncertainty or randomness in this sense.

The entropy of a physical system is proportional to the amount of energy that is no longer available to do physical work in classical physics.

Entropy is central to the second law of thermodynamics, which states that any activity in an isolated system increases entropy.

Entropy cannot be destroyed by any means at any scale, so it cannot decrease overall.

Thus, the correct option is C.

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Answer:

8.69 g

Explanation:

density = 1.1 g/mL

it means,

1 ml of the solution has a mass of 1.1 g

∴7.9 ml of the solution has a mass of =(1.1 x7.9) g

                                                              =8.69 g

Answer:

What following????

Explanation:

Answer:

Can you be more specific

Explanation:

Nitrogen, also known as "N", with a mass of 14.0067 u and the atomic number of 7, is known mostly an element (it is a chemical element) and when it is elements like this, it is in a periodic table (Fun Fact: Nitrogen is colorless and an unreactive odorless gas element.) It is an element.

Hope this helped!

Nate

Answer:true

Explanation:

Answer: most is 3

Explanation:

“Ability to form a compound” is a chemical property.

Answer: Option A

Explanation:

Each element exhibits its characteristic physical and chemical properties. The physical properties of an element describes the boiling point, melting point, freezing point, density, inherent state of matter, electrical and thermal conductivity, etc. The change in physical properties occur when there is a change in the phases and not any change in the chemical composition.

But for chemical properties, these properties explain the bond strength of the elements. It helps to decide the reactivity, flammability of substances. The chemical properties of substance or element decide how easily it can react or get burned.

Any properties or reactions which lead to formation of compounds different from the reactants are considered as chemical change of the reactants. So we can say that the ability to form a compound is a chemical property as in this case, the reactants will react with each other in presence of external heat if required to form the product compound whose chemical composition and properties will be different from the reactants.

Answer:

The staining process will dye them purple (option C)

Explanation:

Gram staining is a method of staining used to distinguish and classify bacterial species into two large groups. Those 2 groups are called Gram- positive and gram - negative groups.

This staining is based on the composition of their cell wall. Gram staining uses crystal violet to stain cell walls, iodine as a mordant, and a fuchsin or safranin counterstain to mark all bacteria.

⇒ Gram- positive bacteria are called gram - positive because they will give a positive result. This according to their cell wand. Their cell wall is typically rich with peptidoglycan and lacks the secondary membrane and lipopolysaccharide layer found in Gram-negative bacteria

Gram- positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured.

⇒ Gram- negative bacteria are called gram - negative because they will give a negative gram result.

Because of the presence of higher lipid content, after the alcohol-treatment, the porosity of the cell wall increases, hence the CVI complex (crystal violet – iodine) can pass through. Thus, the primary stain (crystal violet) is not retained. Gram negative bacteria will appear red or pink.

Yogurt is produced using a culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus bacteria. (In addition, other lactobacilli and bifidobacteria). All of those bacteria are gram-positive, what means they will appear purple.

Answer:

25.872 g of carbon dioxide will produced.

Explanation:

Given data:

mass of butane (C4H10) = 8.21 g

mass of carbon dioxide = ?

Solution:

Chemical equation

C4H10 + O2 → CO + H2O

Balanced chemical equation

2C4H10 + 13O2 → 8CO + 10H2O

First of all we will calculate the moles of butane.

number of moles = mass/ molar mass

number of moles = 8.21 g/ 58 g/mol

number of moles = 0.147 mol

from balanced chemical equation we will compare the moles of C4H10 with CO2,

             C4H10     :    CO2

                2           :      8

              0.147       :      8/2×0.147 = 0.588 moles

now we will calculate the mass of carbon dioxide from moles,

 mass of CO2 = number of moles × molar mass of CO2

 mass of CO2 =  0.588 mol × 44 g/mol

mass of CO2 = 25.872 g

By applying stoichiometry principles to the combustion of butane (C4H10), it is calculated that burning 8.21 grams of butane will produce approximately 24.82 grams of CO2.

The question asks to determine how many grams of CO2 are produced by burning 8.21 g of C4H10 (butane). To solve this, we first need to understand the balanced chemical equation for the combustion of butane, which is C4H10 + 13/2 O2 -> 4 CO2 + 5 H2O. This indicates that for every molecule of butane combusted, 4 molecules of CO2 are produced.

First, calculate the molar mass of butane (C4H10): (4x12.01) + (10x1.008) = 58.14 g/mol. Thus, 8.21 g of C4H10 is 8.21/58.14 = 0.141 moles. According to the balanced equation, combusting 1 mole of butane produces 4 moles of CO2, so 0.141 moles will produce 0.141 x 4 = 0.564 moles of CO2.

Finally, calculate the mass of CO2 produced: 0.564 moles x 44.01 g/mol (molar mass of CO2) = 24.82 grams of CO2.

Answer:

These are the mixtures,compunds,Homogenious mixture,hetrogenios mixture and element:

Explanation:

a. Milk: Homogeneous mixture.

b. Iron nail: Element.

c. Glass: Compound (specifically, an amorphous solid).

d. Sugar: Compound (specifically, a carbohydrate).

e. Bottled spring water: Homogeneous mixture.

f. Distilled water: Homogeneous mixture.

g. Air: Homogeneous mixture.

h. Alloy bicycle frame: Homogeneous mixture (specifically, a solid solution)

i. Propane: Compound (specifically, an alkane hydrocarbon)..

j. Baking soda: Compound (specifically, sodium bicarbonate).

Milk is a homogeneous mixture, iron nail is an element, glass is a compound, sugar is a compound, bottled spring water is a homogeneous mixture, distilled water is a homogeneous mixture, air is a homogeneous mixture, an alloy bicycle frame is a homogeneous mixture, propane is a compound, and baking soda is a compound.

a. Milk - Homogeneous mixture

b. Iron nail - Element

c. Glass - Compound

d. Sugar - Compound

e. Bottled spring water - Homogeneous mixture

f. Distilled water - Homogeneous mixture

g. Air - Homogeneous mixture

h. Alloy bicycle frame - Homogeneous mixture

i. Propane - Compound

j. Baking soda - Compound

Final answer:

The initial step an engineer takes when developing technology to combat ocean pollution is to identify the pollution reduction need, consider the effectiveness of existing methods, and understand the impacts on marine life and biodiversity.

Explanation:

When an engineer is developing new technology to reduce ocean pollution, the first step they would likely take is to identify the need to reduce ocean pollution. This involves understanding the problems caused by pollutants, such as how oil spills can cover the surface of the ocean, reducing light and oxygen penetration and adversely affecting marine life. Engineers must also consider the effectiveness of current methods for dealing with pollution, such as the use of chemicals and bioremediation for oil clean-up, and the impacts of those methods on marine biodiversity and ecosystems. This foundational step frames the direction of subsequent research and design efforts aimed at creating new, effective solutions.

Answer:

- Atoms cannot be divided

- Atoms were named in the fifth century BCE

- Atoms are the smallest unit of matter

Explanation:

- The atom is widely known as the smallest unit matter is made of, which obtains properties of a chemical element.

- Atom can be regarded as indivisible amount of a chemical element having its own existance.

- All states of matter are made of neutral or ionized atoms.

- In the 5th century BCE, the basic concept of atom was by the atomist school in Ancient Greece.

Answer:

A solid has a definite volume and adefinite shape.  

A liquid has a definite volume and no definite shape.  

A gas has no definite volume and no definite shape.

Explanation:

Solids

Solids have a definite volume and definite shape

The particles present in a solid are very closely packed since the intermolecular forces between them are very strong. The molecules do not move apart.

Liquids

Liquids have a definite volume and no definite shape

The particles present in a liquid are closely packed since the intermolecularforces holds the molecules close together. The molecules slide over each other.  Liquids take up  the shape of the container

Gases

Gases have no definite volume and no definite shape

The particles present in a gas are very loosely packed since the intermolecular forces are very weak.  There are no attractive forces between the molecules.  Gases spread through the container

Answer:

A solid has a definite volume and a definite shape.  

A liquid has a definite volume and no definite shape.  

A gas has no definite volume and no definite shape.

Explanation:

Answer:

The number of molecules= 1.33 × 10∧22 molecules

percentage of mercury = 87%

Explanation:

Given data:

mass of dimethyl mercury = 5.10 g

number molecules of dimethyl mercury in 5.10 g = ?

percentage of mercury = ?

Solution:

First of all we will calculate the molar mass of dimethyl mercury.

molar mass of HgC2H6 = 1×200.6 + 2×12 + 6×1 = 230.6 g/mol

we know that,

230.6 g of HgC2H6 = 1 mol = 6.02 × 10∧23 molecules.

so

For the 5.10 g of sample:

5.10 g/230 g/mol = 0.022 moles of HgC2H6

now we will multiply these number of moles with Avogadro number to get number of molecules in 5.10 g of sample.

0.022 × 6.02 × 10∧23 molecules = 0.133  × 10∧23 molecules or

1.33 × 10∧22 molecules.

Percentage of mercury:

Formula:

percentage = (atomic number of Hg × total number of atoms of Hg/ molar mass of HgC2H6) × 100

% age of Hg = (200.6 g/mol× 1/ 230.6 g/mol) × 100

%age of Hg = 0.869 × 100

%age of Hg = 86.99 % or 87 %

There are approximately [tex]\(1.33 \times 10^{22}\)[/tex] molecules in the sample, and mercury constitutes approximately [tex]\(87.00\%\)[/tex] of the sample's mass.

1. Calculate the number of moles of dimethylmercury:

[tex]\[ \text{Number of moles} = \frac{\text{Mass}}{\text{Molar mass}} = \frac{5.10 \, \text{g}}{230.658 \, \text{g/mol}} \approx 0.0221 \, \text{moles} \][/tex]

2. Calculate the number of molecules using Avogadro's number:

[tex]\[ \text{Number of molecules} = \text{Number of moles} \times N_A \approx 0.0221 \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mol} \approx 1.33 \times 10^{22} \, \text{molecules} \][/tex]

3. Calculate the percentage of mercury (by mass) in the sample:

[tex]\[ \text{Percentage of mercury} = \frac{\text{Molar mass of Hg}}{\text{Molar mass of HgC}_2\text{H}_6} \times 100\% \]\[ = \frac{200.59 \, \text{g/mol}}{230.658 \, \text{g/mol}} \times 100\% \approx 87.00\% \][/tex]

So, there are approximately [tex]\(1.33 \times 10^{22}\)[/tex] molecules in the sample, and mercury constitutes approximately [tex]\(87.00\%\)[/tex] of the sample's mass.

Answer: 129

Explanation:Please see attachment for explanation

Answer:

Hypothesis.

Explanation:

Investigation where only the independent variable is being tested by the scientist.

Answer:

Try a magic eraser!

Explanation:

Answer:

All you have to do is put a little rubbing alcohol on a rag or paper towel, rub it over the dried marks, and the Expo marker comes right off. It works on boards, books, and most other Expo marked surfaces (like refrigerators, windows, laminate countertops, etc).

Answer:

living things, fossils, and places

Explanation:

Comparing fossils involves examining similarities and differences in physical form, DNA, and proteins, as well as rock distribution and types to understand evolutionary relationships. The study of taxonomy and evolutionary patterns is enhanced by the integration of genetic data with fossil evidence.

In the context of fossil comparisons, it is critical to know about similar species both from the present and the past, as fossils highlight differences and similarities in forms, shedding light on the evolutionary process. Such comparisons often involve analyzing the anatomy, distribution, and environmental context of fossils.

A key example of this can be found when examining the Archaeopteryx fossil, which shares many features with modern birds, helping to establish evolutionary links. Not only do physical characteristics play a role, but similarities in DNA or protein sequences between species also offer insights into their evolutionary relationships, confirming patterns suggested by the fossil record.

Moreover, different rock types and their distributions, as well as rocks from ancient climate zones, provide additional context that can help determine the age and environment in which these organisms lived. When analyzing a fossil, consider the type of skeleton, its body plan (including symmetry), its likely habitat, and how it might have fed and behaved.

Such information contributes to our understanding of the organism's paleo-environment. The study of index fossils is particularly useful for correlating the age of different rock layers across geographical regions.

Understanding taxonomy and using fossils for comparative anatomy studies are classic methods for reconstructing evolutionary histories.

However, genetics has taken a front seat in comparative studies due to its direct link to the source code of life, allowing for more precise evolutionary timings via mitochondrial DNA (mtDNA) analyses in conjunction with fossil data. Extinct species comparisons to extant ones illuminate evolutionary storylines and highlight continuities and transitions across time.

Answer:

Dependent variable

Answer:

Explanation:

Tools, instruments, apparatus are very key to research works carried out in the laboratory. The more sophisticated they become, the more efficiency they provide in making ground breaking researches.

Over the years, technological advancement has afforded scientists with new way of achieving precision and accuracy in their procedures by developing cutting edge facitlities. These equipment can help carry out better experiment  and make observations simple and easy to do.

Explanation:

laboratory tools improve the observations made by a scientist in the following ways:

Answer: Hill is a Major characteristic used to differentinate between a plain and plateau

Explanation:

Answer:

The final volume must be 400 mL.

Explanation:

Let us assume the Initial volume as 100ml

Using dilution factor formula  

[tex]\\$M_{1} \times V_{1}=M_{2} \times V_{2}$\\\\$0.400 M \times 100 m l=0.100 M \times V_{2}$[/tex]

So,

[tex]$V_{2}=\frac{0.400 M \times 100 m l}{0.100 M}=400 m l$[/tex]

Thus, the final volume must be 400 mL.

Explanation:

Molarity of HCl ,[tex]M_1= 0.400 M[/tex]

Volume of the HCl solution = [tex]V_1=500mL[/tex] (assume)

Molarity of HCl after dilution [tex]M_1= 0.100 M[/tex]

Volume of new HCl solution = [tex]V_2[/tex]

[tex]M_1V_1=M_2V_2[/tex]

[tex]0.400 M\times 500 mL=0.100 M\times V_2[/tex]

[tex]V_2=\frac{0.400 M\times 500 mL}{0.100 M}=2000 mL[/tex]

[tex]\frac{V_1}{V_2}=\frac{500 mL}{2000 mL}[/tex]

[tex]V_2=4\times V_1[/tex]

In order to dilute a HCl solution from 0.400 M to 0.100 M the final volume must be 4 times the initial volume of 0.400 M HCl solution .