What is the de Broglie wavelength of an electron traveling at 1.62×105 m/s ?

Answer:

There are 2.55 moles of water.

Explanation:

First you have to calculate the molar mass fo water ⇒ 18 grs/mol.

Then 18 grs ----------- 1 mol H2O

        45.9 grs ------- 2.55 moles of H2O

There are 2.55 moles of water.

Answer:

8

Explanation:

because 14-6 is 8

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.

To find more on experimental replication, refer here:

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Answer:

If a substance undergoes a physical change, then it will retain most of its original properties because no new substance is formed.

If a substance undergoes a chemical change, then it will not retain its original properties because a new substance is formed.

Explanation:

So in shorter words its options 2 and 3

All four statements are appropriate hypotheses reflecting the distinctions between physical and chemical changes. Physical changes involve alterations in the state or form without changing the chemical identity, whereas chemical changes result in the creation of new substances.

When addressing the question regarding whether certain statements about physical and chemical changes are appropriate hypotheses, it's important to recognize that an appropriate hypothesis should be testable and based on scientific concepts. The statements provided can be evaluated based on our understanding of physical and chemical properties and changes.

These statements align with the fundamental distinctions between physical and chemical changes. A physical property change affects the form but not the chemical identity of a substance, whereas a chemical property change results in the formation of a new substance.

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Calcite comes from limestones and limestones are sedimentary.

So calcate is sedimentary rock

Answer:

g(x) = 2 always

Explanation

No matter the value, even if you write F(x), its value is always 2! SKSKSKSKS PERIOD !!!!!

The product of the two functions f(x) and g(x), represented as (f · g)(x), is found by multiplying the equations together. The resulting equation after applying distributive property is 6x^3 - 15x^2 + 4x - 10.

The question asks for the product of two functions, f(x) and g(x). This is denoted as (f · g)(x), which is the multiplication of respective function values.

The functions given are f(x) = 2x - 5 and g(x) = 3x^2 + 2. To find (f · g)(x), we multiply these two functions together.

(f · g)(x) = (2x - 5)(3x^2 + 2).

Using distributive property, the result is: 6x^3 + 4x - 15x^2 - 10

So, (f · g)(x) = 6x^3 - 15x^2 + 4x - 10 is the product of the two functions.

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Answer:

Explanation:

Amino acids consist of an amine (-NH2) group and a carboxyl acid (-COOH) group. So they have elements such as Nitrogen (N), Hydrogen (H), Carbon (C) and Oxygen (O).

Amino acid composition:

The human body has 20 amino acids which are all important but there are only 9 that are essential for the human body.

Best of Luck!

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:

The boiling point of the water by adding 2.5 moles of aluminium nitrate will be changed by 4° C.

Explanation:

Step 1: define the formula for an elevation of the boiling point

Δ T b  = i *K b *bB

⇒with Δ T b = the elevation of the boiling point ( in °C or Kelvin)

⇒with i = van't Hoff  i -factor for the solute. The factor i shows the number of individual particles (typically ions) that are formed by a compound in the solution.

⇒ with Kb = ebullioscopic constant, which depends on the properties of the solvent. (Eventually can be calculated).

⇒ with bB= the molal concentration (molality) of the solute.

Since we have 2 different solutions ( component 1 = sugar and component 2 = aluminium nitrate) of the same molality in the same solvent ( water). We can express this as followed:

Δ T b,2 / Δ T b,1  = (i2 * Kb * bB ) / (i1 * Kb *bB)

⇒after he was simplifying this becomes:

Δ T b,2 / Δ T b,1  = i2 / i1

⇒ Now we can isolate either Δ T b,2 or Δ T b,1:

Δ T b,2  =(i2/i1) x Δ T b,1

Sugar

⇒ is a covalent compound, so it doesn't dissociate in water ⇔ i1=1

Aluminium nitrate

⇒ it's a soluble ionic compound and in solution it will dissociate as the following equation:

Al(NO3)3 (aq) → Al3+(aq)  + 3NO3- (aq)

⇒thus here are 4 particels formed : 1 Al3+ + 3NO3-

i2=4

As given, we also know that the temperature was raised by 1°C after adding sugar ⇒ Δ T b,1 = 1°C

Step 2: insert all the numbers in the formula for boiling point elevation

(i2/i1) x Δ T b,1

(4/1 ) x 1°C = 4°C

⇒ The boiling point of the water by adding 2.5 moles of aluminium nitrate will be changed by 4°C

Answer:

30 kg x 9.9m/s=297 N

Explanation:

When, a 30 kg child were running at a rate of 9.9 m/s, then child's kinetic energy is 1470.15 joules.

The student's question is concerned with calculating the kinetic energy (KE) of a child running at a certain speed. Kinetic energy can be calculated using the formula KE = (1/2)mv₂, where m is mass and v is velocity. In this case, since the student has provided the values of the child's mass (30 kg) and the speed (9.9 m/s), we can compute the kinetic energy.

First, square the velocity: 9.9 m/s imes 9.9 m/s = 98.01 m/s². Next, multiply this value by the mass of the child and then divide by 2 to get the final kinetic energy:

KE = (1/2)imes 30 kg imes 98.01 m2/s2 = 1470.15 J (joules).

Therefore, the kinetic energy of a 30 kg child running at 9.9 m/s is 1470.15 joules.

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 .

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

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:

Option =C each mouse in the study has brown ears.

Explanation:

Qualitative:

Qualitative properties are those that can be only observed but not measured in numerical values. These are observed through senses: touch, sight, smell, taste and hear.

For example:

Color, odor, brittleness, taste etc.

Quantitative:

Quantitative properties can be measured in numerical values.

For example:

Melting point, boiling point, conductivity, viscosity, density, hardness and solubility.

In short we can say that qualitative is a measure of quality while the quantitative is a measure of quantity.

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: 129

Explanation:Please see attachment for explanation

Answer:

The Kelvin temperature scale reflects the relationship between temperature and average kinetic energy.

Explanation:

The Kelvin temperature of a substance is directly equal to the average kinetic energy of the particles of a substance.

Answer:

Is a direct relation among them

Explanation:

As you increase the kinetic energy of the molecules, the temperature will increase, if the molecules have more energy, will move faster.

Check the graphic.

When the particles absorb some energy from the surroundings, it will start to save it, until the element do not want to be in a compound or in a certain state of matter, it will be independent

Hope this info is useful.

Answer:

B is wrong

Explanation:

I took a test just now and got it wrong

The indicators of a chemical change are represented in this scenario is the formation of a gas.

A chemical change is a change in the substance's chemical properties and its physical properties. The chemical changes show that a chemical reaction occurred.

Thus, the correct option is C) formation of a gas.

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Heat is released.

When a chemical change occurs, energy comes out of the atoms which causes heat.

Answer: Option (A) is the correct answer.

Explanation:

Chemical changes are defined as the change which tend to show difference in chemical composition of a substance.

For example, toxicity, reactivity, combustion etc are all chemical properties.

So, in the given situation formation of bubbles shows that a gas has been formed which is a chemical change.

A chemical change will always lead to the formation of a new compound and this change is irreversible in nature by any physical means.

On the other hand, a change which is unable to bring any difference in chemical composition of a substance is known as a physical change.

For example, change in shape, size, mass, volume etc are all physical properties.

Thus, we can conclude that a gas is formed is an indication that a chemical change has occurred.

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:

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.

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:

In the given question Brianna is trying to make a whole figure by combining different  single elements.

Explanation:

Here are the different  coloured that are used to join and make one piece this method that Brianna is following is called synthesis.

The combination here is of simple substances that are combined directly to make a complex compound. The compound formed is complex while the substances that combined together can be element or compound  or a combination of both.

Answer: synthesis

Explanation:

Answer:

so measuring stuff is easier and simple

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:

Thermal Conductivity

Explanation:

The dependent variable is what is being measured in the experiment and it's affected by the independent variable. Thermal conductivity is the best answer, because you are trying to find out which wire is a better conductor of thermal conductivity. Basically, which one conducts more heat? The copper does, because when its put into the hot water it melted more of the wax than the steel wire did.

Answer: Thermal conductivity of wire

Explanation:

The hypothesis of the experiment is to find the thermal conductivity of the the wires. The independent variable in the experiment is the type of wire used.

There are two types of wire used in the experiment one is copper and other one is steel. Rest all the variables are control variable.

At the end of the experiment the thermal conductivity was determined. This is the dependent variable of the experiment.

Hence, the correct answer is option D

Answer:

What following????

Explanation:

Answer:

Can you be more specific

Explanation:

Answer:

9.99 ml water will be delivered from pipet

Explanation:

When Water is being delivered by the pipet the temperature is 19 degree Celsius. Also know that dependence of density is on temperature although this temperature dependence is inverse in nature that is when temperature increases density decreases and vice versa.

Now we also know the density of water at 20 ° Is [tex]0.99 gml-1[/tex].

At this temperature 9.98 gram will occupy a volume= [tex]0.98/0.998= 9.997ml[/tex]