i am timed please help

Answer:

The number of valence electrons determines an element's reactivity, or how likely the element is to react with other elements.

Explanation:

Answer:

A) 62.5 HB

B) 75 HB

C) 95 HB

D) 90 HB

Explanation:

From the attached animated figure, we can trace the values of hardness (HB) for each of the alloys.

The scale we are using in the attachment to read our values for HB is the HRB scale that shows the Rockwell hardness on the right hand side.

A) For 0.25 wt%C with spheroidite, Tracing the line out on the green curve and reading the scale on the right, the hardness is approximately 62.5 HB

B) For 0.25 wt%C with coarse pearlite, Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 75 HB

C) For 0.60 wt%C with fine pearlite, Tracing the line out on the red curve and reading the scale on the right hand side, the hardness is approximately 95 HB

D) For 0.60 wt%C with coarse pearlite. Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 90 HB

A race car at the Daytona 500 zips around the track its travel the first 80 km in 0.4 hours, the next 114km take 0.6, the following 80 km take 0.4, so the average speed is 195.71 km/hr.

Average speed of any body will be calculated by dividing the total time to cover the ditance from the total distance covered.

Total distance to cover = 80km + 114km + 80km = 274km

Total time to cover distance = 0.4hr + 0.6hr + 0.4hr = 1.4hr

Average speed of car = 274/1.4 = 195.71 km/hr

So, the average speed of car is 195.71km/hr

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Answer:

The  correct option is  c

Explanation:

The chemical equation for the reaction of  Z-4,5-dimethyloct-4-ene and HCl is shown on the first uploaded image

Now looking at the product we see that there are two who has four different groups attached to them this carbon are known as chiral carbons hence the product formed is a pair of diastereomers

Answer:

Explanation:

The major difference between pure and applied chemistry is the purpose and intent of the study.

Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.

Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application

The major difference between pure and applied chemistry is the purpose and intent of the study.

Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.

Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application.

Thus,the major difference between pure and applied chemistry is the purpose and intent of the study.

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Answer:

Transcription is when you make a copy of the RNA from DNA. This is how the mRNA can leave the nucleus which exists to the cytoplasm and into ribosomes where protein synthesis occurs. Translation is what happens after transcription and this is where protein synthesis occusrs in the ribosomes/endoplasmic reticulum.

Explanation:

Answer:

There are many different price adjustment strategies which can be implemented in the current market.

Explanation:

Psychological pricing:

Psychological pricing is a strategy in which the price of a product is displayed with mostly one cent difference so the whole number shown is less by $1 and this difference can get higher if the price of the product is more.

Example 1: The price for a toy in a toy shop is $4.99, if rounded this will be $5 but the whole number visible is $4.

Example 2: The price of a laptop is $193, this again is nearly $200 but the price is reduced by $7 in order to influence their customers into buying the product.

Example 3: The price of a car is $35,995, this again is about $36,000 but the buyer may be influenced by this technique and result in purchasing the product with such price.

Geographical Pricing:

Geographical pricing is a strategy where different prices are charged in different outlets, this strategy is made keeping in mind the purchasing power of the locality, if the local people can pay higher price for a product then the price is high there but same product may have a lower price in an area where people can not pay high price.

Example 1: Price of a T-shirt is $15 in a posh area while the price of the same T-shirt is $5 in an area with poor locality.

Example 2: Price of a hair brush is $10 in a poor area while the same brush is available in a posh area at a rate of $35.

Example 3: Price for a food item is $6 in a restaurant in posh area while the same burger is available for $3 in a restaurant in a poor area.

Answer:

It is no. D

Explanation:

Many meteoroids are formed from the collision of asteroids, which orbit the sun between the paths of Mars and Jupiter in a region called the asteroid belt.

Answer:

0.773 mole

Explanation:

From the question given above, the following were obtained:

Mass of dinitrogen oxide (N₂O) = 34 g

Mole of N₂O =.?

Next, we shall determine the molar mass of N₂O. This can be obtained as follow:

Molar mass of N₂O = (14 × 2) + 16

= 28 + 16 = 44 g/mol

Finally, we shall determine the number of mole in 34.0 g of dinitrogen oxide (N₂O) as follow:

Mass of dinitrogen oxide (N₂O) = 34 g

Molar mass of N₂O = 44 g/mol

Mole of N₂O =.?

Mole = mass /Molar mass

Mole of N₂O = 34/44

Mole of N₂O = 0.773 mole

Therefore, 0.773 mole is present in 34 g of dinitrogen oxide

Answer:

a. control everything the cell does

Explanation:

the nucleus is like the brain of the cell

Answer:

aqueous acid is used as a reagent.  

Explanation:

Addition of Grignard reagent in aldehyde and followed by the acidification give rise to the primary or secondary alcohol. when the formaldehyde is used than the primary alcohol is formed otherwise secondary alcohol is formed.

in this reaction we also use the aqueous acid for the acidification as a reagent. We add aqueous acid when ethanol is present. This is because ethanol is get converted in the presence of aqueous acid into the chloroethane.  

Answer:

A. Making decisions that help humans survive

B. Developing technologies that help humans thrive

C. Developing explanations based on facts

E. Gathering facts that explain natural events

Explanation:

The above are examples of the practices of how humans use science.

Science has been of tremendous help to humans in making decisions that make humans survive and develop technologies that help humans thrive. It has helped to gather and develop explanations that are based on facts. It has helped to explain natural events.

Answer:

Dissolves a chemical sample well at high temperatures.

Does not dissolve a chemical sample well at low temperatures.

Explanation:

Recrystallization involves the dissolution of the solute in a solvent at high temperature. As the solution cools, it becomes saturated and the solute crystallizes out of the solution.

A good recrystallization solvent must only dissolve the solute at high temperature and must not dissolve it at low temperature. Hence, these are the two conditions required for any good recrystallization solvent.

Answer:

speed = 3.7/46 = 0.080m/s

d= 3.7m

t= 46s

Explanation:

In Au₂SO₄, the charge on each gold atom is +3.

The charge on the transition metal gold (Au) in Au₂SO₄ can be determined by considering the overall charge of the compound and the charges of the other ions present. In this case, the sulfate ion carries a charge of -2.

Charge on Au: +3

In Fe₂(CrO₄)₃, the transition metal iron (Fe) is present. The compound contains two iron atoms. To determine the charge on each iron atom, the charges of the other ions in the compound. The chromate ion carries a charge of -2, and the compound as a whole is neutral.

Charge on Fe: +3

The transition metal zinc (Zn) is present in Zn(OH)₂. To determine the charge of the zinc ion, to consider the charges of the other ions. The hydroxide ion (OH-) carries a charge of -1. Since there are two hydroxide ions, their combined charge is -2.

Charge on Zn: +2

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Answer:

The best thermometer to use for this temperature is the alcohol-in-a -glass thermometer.

Explanation:

The alcohol thermometer is a type of thermometer which uses ethanol as its thermometric liquid. This has some advantages at low temperatures because ethanol freezes at about −114.9 °C  that is (−174.82 °F).

Due to its low freezing point, it can still function effectively as a thermometric liquid, expanding and contracting properly based on the applied heat,  when dealing with temperature measurements that are at about -38.2°F.

The higher Gas pressure inside the balloon. Hence, option A is correct.

In a molecule, the kinetic energy existing is "directly proportional" to the temperature of the molecule. If one of the values increases, then the other value also increases and vice-versa.

The higher Gas pressure inside the balloon. As the number of collisions with the wall of the balloon increases, the pressure inside increases.

Hence, option A is correct.

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Answer:

The answer is

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

From the question

volume of ethanol = 87.94 mL

density = 0.79 g/mL

The mass of ethanol is

mass = 87.94 × 0.79

mass = 69.4726

We have the final answer as

Hope this helps you

Answer:

The answer is 1.61 × 10²³ atoms

Explanation:

To determine number of atoms, we will use the formula below

Number of atoms = number of moles (n) × avogadro's constant (6.02 x 10²³)

n was not provided, hence we will solve for n

n = mass/ molar mass

molar mass of carbon monoxide, CO (where C is 12 and O is 16) is 12 + 16 = 28

mass was provided in the question as 7.48

n = 7.48/28

n = 0.267

Hence,

number of atoms = 0.267 × 6.02 x 10²³

= 1.61 × 10²³ atoms

Answer:

170ml

Explanation:

multiply the volume value by 100000

Answer:

[tex]m_{water}=50.25g[/tex]

Explanation:

Hello,

In this case, considering that the by-mass percent of water is:

[tex]\% m/m=\frac{m_{water}}{m_{sample}}*100\%[/tex]

Given such percent and the mass of the sample, we can find the mass of water in grams in the sample by solving for it as shown below:

[tex]m_{water}=\frac{\%m/m*m_{sample}}{100\%}\\ \\m_{water}=\frac{25\%*201g}{100\%}\\ \\m_{water}=50.25g[/tex]

Best regards.

Answer:

Diet Dr. Pepper

Explanation:

The density of an object and the liquid involved determines if that particular object will float or sink in the particular liquid. An object will FLOAT if its density is lower than that of the liquid substance while it will SINK if its density is higher than that of the liquid substance.

In this case, water (lake) is the liquid substance. According to the question, an unopened 350 mL can of DIET Dr. Pepper will float in a lake because it is less dense than the water while an unopened 350 mL can of REGULAR Dr. Pepper will sink because it is more dense than water.

Hence, the DIET type of soda is the least dense

Answer: To evaluate the claim in the advertisement, Travis should look at the data for the control group to see how much the fish grew without the new food.

Explanation:

Answer:

Because both compounds (CaCl2 and CaBr2) contain elements (bromine and chlorine) from the same group (group 7)

Explanation:

Elements are organized into groups on the periodic table based on the number of valence electrons contained in their outermost shell. These elements in the same group i.e. same number of valence electrons, will behave in a similar manner chemically.

CaCl2 and CaBr2 are two compounds that contains elements (Chlorine and Bromine) from the same group, which is group 7. Elements in group 7 are called HALOGENS and have 7 valence electrons in their outermost shell.

Bromine (Br) and Chorine (Cl) are responsible for the similarity in the properties of CaCl2 and CaBr2 because the Chlorine and Bromine contained in them will cause them to react similarly and behave similarly in the presence of other compounds.

Answer:

This question is incomplete, the complete question is; assuming that the solution has a specific heat of 4.18 J/g°C

The answer is 381.67 J/g

Explanation:

Enthalpy change denoted by ΔH can be calculated using the formula;

ΔH = m × c × ΔT

Where; m= mass of reactants

c= specific heat

ΔT = change in temperature

ΔT = T2 - T1

ΔT = 32.76 - 19.3

ΔT = 13.46 °C

mass of reactants= 85.6 + 14.8 = 100.4g, c = 4.18J/g°C

Hence; ΔH = m × c × ΔT

ΔH = 100.4 × 4.18 × 13.46

ΔH = 5648.78J

Enthalpy change per gram of potassium hydroxide dissolved in the water is;

ΔH = 5648.78/14.8

ΔH = 381.67 J/g

The enthalpy change per gram of potassium hydroxide dissolved in the water is 382 J/g

Q = MCΔT

Q = 100.4 × 4.184 × 13.46

Q = 5654.19 J

ΔH = Q / g

ΔH = 5654.19 / 14.8

ΔH = 382 J/g

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Answer:

Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat, a flow of energy, when a body is in contact with another that is colder. Temperature is measured with a thermometer.

Answer:

The degree or intensity of heat present in a substance or object

Answer:

Consult labels or instructions before disposing of it. Always wear the proper personal protective equipment. Put all cleaning paper towels in the trash

Explanation:

Gloves should never be removed when disposing of waste, since these can contain infected fluids or even cultivated microorganisms that are pathogens for our lives and can enter through a lesion of the continuity solution of the epithelium in our hands.

In other words, if there is a wound, and it is contaminated with waste by not wearing gloves, the risk of contracting diseases is much greater.

Answer:

its, b

Explanation:

took the test on e2020

Carbon-14 dating cannot be used to date ancient rocks because:

B. Carbon-14 decays relatively quickly.

It is a method for tracking down the time of natural materials, like wood, in light of their substance of radioactive carbon. Also, it is a technique for estimating the time of natural matter by investigating its carbon content.

The decay takes place around 55,000 years i.e half the amount of the radioisotope present at any given time.

Thus, option B is correct.

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Answer:

Explanation:

The movement of the electrons is illustrated in the picture attached to this answer. It is a four-step reaction mechanism.

First STEP: The first step involves the transfer of an electron from sodium to form a radical anion.

Second STEP: This radical anion then removes a proton/hydrogen from ammonia in a bid to neutralize itself (hence the hydrogen becomes bonded to the anion).

Third STEP: The sodium (from NaNH₂ formed) transfers an electron again to produce a vinyl carbanion.

Fourth STEP: The carbanion then removes a proton/hydrogen from ammonia (like in the second step) to form a neutral trans-alkene.

NOTE: The circled numbers denote each step while the mechanism on the left represents the use of any alkyl group (R and R') while the mechanism on the right assumes both alkyl groups are methyl. Hence, 2-butyne started the reaction and the final product was trans-2-butene.