Help me answer these questions

Answer:

C

Explanation:

Single replacement reactions is when only one element gets replaced / changed. This usually looks like this: A + BC = B + AC or A + BC = C + AB

Therefore, the number of reactants must be equal to the number of products, since no actual combinations / break ups are occurring.

Answers A and D are eliminated right away since the number of products don't equal the number of reactants.

Answer B is wrong because it does not show simply one element being replaced, instead, two compounds are being formed. It doesn't look like the example given.

Only answer C shows that one element is replaced:

The iodine is replaced with bromine to form NaBr + I2

The chemical equation NaI + Br₂ --> NaBr + I₂ is an example of single replacement reaction.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

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Answer:

1 ninth of the room

Explanation:

Answer:

Mass = 525.36 g

Explanation:

Given data:

Mass of CO₂ formed = ?

Mass of CH₄ burned = 191 g

Solution:

Chemical equation:

CH₄ + 2O₂     →     CO₂ + 2H₂O

Number of moles of CH₄:

Number of moles = mass/molar mass

Number of moles = 191 g/ 16 g/mol

Number of moles = 11.94 mol

Now we will compare the moles of CH₄ and CO₂.

                CH₄          :          CO₂

                 1              :            1

                11.94        :         11.94

Mass of  CO₂:

Mass = number of moles × molar mass

Mass = 11.94 mol × 44 g/mol

Mass = 525.36 g

Answer:

a . Mixture

Explanation:

When solids, liquids and gases mix with one another, the product is usually a mixture.

Mixtures are classified as impure substances because:

Pure substances are elements and compounds with typically definite compositions.

So, when substances in different phases combines, an heterogeneous mixture is produced.

Answer:

D

An unmagnetized block of metal, which has a top and a bottom

Answer:

OH- as alkalis produce hydroxide ions when dissolve in water

Answer:

Explanation:

Any factor that increases the Collison rate definitely increase the rate of reaction, concentration, temperature, surface area, pressure and catalyst are the major factor that affect the rate of reaction.

The rate of reaction is the study of change of concentration of reactant or product with respect to time.

There are so many factors that affect the rate of reaction

1)concentration: As the concentration of reactant increases the number of collisions increases so rate of reaction also increases.

2)temperature: As the temperature increases the movement of gaseous molecule increases hence the Collison rate increases and hence the rate.

3)surface area (for solid reactants ONLY): As the surface area of the catalyst increases, more molecule can sit on the reactive site hence more is the rate of reaction.

4)pressure (for gaseous reactants ONLY): As pressure increases the randomness increases and hence the Collison and hence the rate of reaction

5)catalyst: Catalyst increase the rate of reaction as they decrease the activation energy

Thus concentration, temperature, surface area ,pressure and catalyst are the factor that increases rate of reaction

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Answer:

conditioning-the process of associating a stimulus with a good or bad outcome.

trial-and-error learning-the process of performing a behavior more and more skillfully.

insight learning-the process of using prior knowledge to solve a problem.

imprinting-a bond to an indivisual or object shortly after birth or hatching.

Explanation:

Did this assignment.

Answer:

Insight learning=2 one

conditioning=4th one

Imprinting=1st one

Trial-and-error learning=3rd one

(If urs is not in the same order here is the written one)

Insight learning-the process of using prior knowledge to solve a problem

Conditioning-the process is associating a stimulus with a good or bad outcome

Imprinting-a bond an individual or object shortly after birth or hatching

Trial-and-error learning-the process of performing a behavior more and more skillfully.

Explanation: hope it helps got it right on edu 2021

Answer:

D. Water vapor in the air condenses to form liquid water or ice

Explanation:

took test on e2020

Answer:

Nutrients

Explanation:

Materials that are moved by runoff nutrients.

A substance that provides nourishment essential for the maintenance of life and for growth. A chemical compound (such as protein, fat, carbohydrate, vitamin, or mineral) contained in foods. These compounds are used by the body to function and grow.

Nutrients are the components found in our food such as carbohydrates, vitamins, minerals, fats, etc. These components are necessary for living organisms to survive. Plants produce their own food while animals and human beings do not produce their own food.

Therefore, Materials that are moved by runoff nutrients.

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Answer:

In the periodic table of the elements, it is expected to be an s-block element, an alkali metal, and the first element in the eighth period. It is the lightest element that has not yet been synthesized.

...

Answer: Matter is made of atoms. Solids, liquids, gases, and plasma are all matter. When all atoms that make up a substance are the same, then that substance is an element. Elements are made of only one kind of atom.

Explanation:

Answer:

Some areas of the body are more sensitive than others because they have more nerve endings. It hurts when you bite your tongue because the sides of your tongue have a lot of nerve endings that are very sensitive to pain! The tongue, lips, and fingertips are the most touch-sensitive parts of the body.  The parts of your skin that need to be most sensitive like your fingertips and your lips have more receptor cells in them than others less sensitive areas.  The least sensitive skin on the human body is found in the heel area. This is because there are very few nerves in the heel to feel things. If there were too many nerves in our heels then walking would be far too painful.

Explanation:

Answer: Some parts of the body are more sensitive than others because they each play an important role. For example, it hurts to bite your toungue because it has a lot of nerves.

Explanation:

Answer:

C.   0.001 second

Explanation:

Millisecond is a subunit of a second.

 Milli depicts a unit to the power of 10⁻³

So;

       1 millisecond  = 10⁻³ s

Therefore,

           1 x 10⁻³   = 0.001s

The solution to this problem is choice C which is 0.001 second

Answer:

Aloeride is a polysaccharide that comprises only 0.015% of the crude A. vera juice material (dry weight). It has a molecular weight between 4 and 7 million Da with its glycosyl components containing glucose (37.2%), galactose (23.9%), mannose (19.5%) and arabinose (10.3%).

Answer:

Aloeride is a polysaccharide that comprises only 0.015% of the crude A. vera juice material (dry weight). It has a molecular weight between 4 and 7 million Da with its glycosyl components containing glucose (37.2%), galactose (23.9%), mannose (19.5%) and arabinose (10.3%).

Explanation:

Answer:

Heterogeneous mixtures are not uniform throughout.

Explanation:

Heterogeneous mixtures are not uniform throughout.

Answer: the second one multiplication

Explanation:

Answer:

Electrons would easily move through the person if there was no rubber around the wire.

Explanation:

The black rubber material is an insulator and will not allow the conduction of heat or electrical current through it. Electrical currents are generated by the movement of electrons through materials.

Hence, if there was no rubber covering around the power cord, the person that plugged-in the power cord would have experienced electric shock because electrons would easily move through him/her from the wire.

Answer:

[tex]0.15008\ \text{g}[/tex]

[tex]3.23\times 10^{21}[/tex]

Explanation:

1 mol of nitrogen at STP = 22.4 L = 22400 cc

n = Mol of [tex]N_2[/tex] = [tex]\dfrac{120}{22400}=0.00536\ \text{mol}[/tex]

M = Molar mass of [tex]N_2[/tex] = [tex]28\ \text{g/mol}[/tex]

[tex]N_A[/tex] = Avogadro's number = [tex]6.022\times 10^{23}\ \text{mol}^{-1}[/tex]

Mass of [tex]N_2[/tex] is

[tex]m=nM\\\Rightarrow m=0.00536\times 28\\\Rightarrow m=0.15008\ \text{g}[/tex]

Mass of the nitrogen is [tex]0.15008\ \text{g}[/tex]

Number of molecules is given by

[tex]nN_A=0.00536\times 6.022\times 10^{23}=3.23\times 10^{21}\ \text{molecules}[/tex]

The number of molecules present in it are [tex]3.23\times 10^{21}[/tex]

Answer:

Mass = 154.95 g

Explanation:

Given data:

Mass of sodium react = 115 g

Mass of sodium oxide formed = ?

Solution:

Chemical equation:

4Na + O₂        →     2Na₂O

Number of moles of sodium:

Number of moles = mass/molar mass

Number of moles = 115 g/ 23 g/mol

Number of moles = 5 mol

Now we will compare the moles of sodium and sodium oxide.

                Na         :          Na₂O

                  4          :             2

                   5         :          2/4×5 = 2.5 mol

Mass of sodium oxide:

Mass = number of moles × molar mass

Mass = 2.5 mol ×  61.98 g/mol

Mass = 154.95 g

Answer:

In the early part of the 20th century, geologists studied the vibrations (seismic waves) generated by earthquakes to learn more about the structure of the earth's interior. They discovered that it is made up of these distinct layers: the crust, the mantle, and the core.

Answer:

The answer is A: Quantities of thousands are more common than quantities of trillions.

Explanation:

It's just kind of process of elimination. None of the other answers make as much sense

Answer:

4.567 ltr

Explanation:

both are gases

so

N2 +Br2 =NBr3

balancing

N2 +3B2 = 2 NBr3

now

3 litr of B2 gives 2 liter of NBr3

6.85 litr of B2 gives 2/3 *6.85 litr NBr3 = 4.567ltr

Answer:

b)4.46 L/hr

Explanation:

To solve this question we need to convert the mL to liters (Using the conversion of 1000mL = 1L) and convert the time from seconds to hours (3600s = 1hr)

mL to L:

1.24mL/s * (1L / 1000mL) = 0.00124L/s

seconds to hours:

0.00124L/s * (3600s / 1hr) = 4.46L/hr

Right answer is:

Answer:

4.79x10¹³s⁻¹

Explanation:

For a first order reaction, the graph of ln k against 1/K follows Arrhenius equation:

lnK = ln A - Ea/RT

Where A is pre-exponential factor, Ea is activation energy, R gas constant and T is absolute temperature

If you graph ln k = y and 1/T = x:

y = lnA - Ea/R x

Where the slope = -Ea/R

And the intercept = lnA

To solve the pre-exponential factor:

31.5 = lnA

e^31.5 =

s⁻¹ because the reaction is first order.

The pre - exponential factor is obtained form the information given ion the question as  4.79 × 10^13 s−1.

For a first order reaction, the Arrhenius equation is written as;

lnk = (-Ea/R)1/T + lnA. This is similar to the equation of a straight line, y = mx + c.

The pre-exponential factor is the intercept (c). Hence;

ln A = 31.5

A = e^31.5

A = 4.79 × 10^13 s−1

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Answer:

option C. Addition of protons to the atomic nucleus.

Explanation:

Elements are fundamentally made up of atoms. Atoms in turn has three sub particles.

These particles are; neutrons, electrons and protons.

The sub particles responsible for the mass of an atoms is basically the protons and neutrons. Going through the options;

The correct option is option C. Addition of protons to the atomic nucleus.