A block is pulled 0.90 m to the right in 2.5 s.

What is the block’s average speed to the nearest hundredth of a m/s?

Answer:

1. False

Balanced forces would mean all forces acting upon an object would be equal. So there is no movement.

2. True

Unbalanced forces would mean there is a force acting upon a side of tge object, causing it to move in a direction.

Answer:

SeCl₆ < SeF₂ <  SeO₂

Explanation:

To determine the order of the bond angle of the compound, we need to determine the hybridization of each compound given.

For:

SeO₂, The hybridization is sp² because the Se is doubly bonded to O at both sides and Se contains a lone pair of electrons.

SeCl₆, Se is attached to six different Cl atoms via a single bond in a hexagonal shape. Thus, SeCl₆ hybridization is sp³d²

SeF₂, Here, Se is singly bonded to F atoms on both sides and Se contains a lone pair of electrons. The hybridization is sp³

Therefore, the bond angle in sp² = 120°, sp³ = 109.8°, sp³d² = 90°

Hence, the order is:  SeCl₆ < SeF₂ <  SeO₂

Answer:

A. modern organisms closely resembling fossils

Explanation:

Fossils are defined as the preserved remains or traces of living organisms from past.

Fossils are considered as an evidence for evolution because they represent the existence of life on earth and shows the difference between the life in past that life on earth today. With the help of fossil, it is easy to determine the age of fossils which further help to determine that how modern organisms have evolved from the past.

Hence, the correct answer is "A. modern organisms closely resembling fossils".

Answer:

D

Explanation:

pretty sure D

Answer:

Coffee

Explanation: When a liquid is warm the particles move faster

Answer:

- ClO₂: it is chlorine dioxide.

- ClO₂⁻: it is the chlorite ion.

Explanation:

Hello!

In this case, since Cl stands for chlorine and O stands for oxygen, being the first compound an oxide and the second one an ion, we can reason:

- ClO₂: it is chlorine dioxide and as its name indicates it, it is an oxide with neutral charge, actually, a molecular compound formed by one chlorine atom and two oxygen atoms.

- ClO₂⁻: it is the chlorite ion in which chlorine has +3 as the oxidation state and therefore it is not neutral but negative as it is ready to bond with a positive ion (cation).

Best regards!

Answer:

A superposition says that the newest rocks are nearer to the surface and oldest are near the bottom

Answer:

A.

Explanation:

Answer:

B.

Explanation:

If it's coming from the south and pushing it north then it'll speed up the marble

Time of decays approximately 2.853 days

Given

mass = 320mg iodine-131

No=320 mg

Nt=250 mg

t1/2 = 8 days

Required

t=time of decays

Solution

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

Input the value

[tex]\tt 250=320.\dfrac{1}{2}^{t/8}\\\\log\dfrac{25}{30}=t/8.log~0.5\rightarrow t=2.853~days[/tex]

Answer:

It will make magnesium oxide and water

Explanation:

Answer: oxide

Explanation:..

Answer:

Light

Explanation:

1 They were not albe to see at night because it  was dark so the lack of light caused them to use echolocation.

Hope this helps

Answer:

Structure 1- dodecanoic acid (lauric acid)

Structure 2- hexadecanoic acid (palmitic acid)

Structure 3- octadecanoic acid (stearatic acid)

Explanation:

Fatty acids are  carboxylic acids having long aliphatic chain. The chain may be either saturated or unsaturated. There are many naturally occurring fatty acids having unbranched chain of an even number of carbon atoms.

Usually, the common name of the fatty acid is not related to its systematic name. Its systematic name is obtained by IUPAC nomenclature.

The images shown are the skeletal structures of lauric acid, palmitic acid and stearic acid. I have written the names of the acids because the question specifically mentions that the compounds are fatty acids and not their salts.

Answer:

The answer to this question is given below in this explanation section.

Explanation:

                       "mutation can contribute to the development of many types of cancers"

About genetic mutations:

There are the two basic type of genetic mutations

Acquired mutations:

These are the most common cause of cancer.They occur from damage to genes in a particular cell during a personal life.For example this could be a breast cell or a colon cell,  with the goes on to divide many times and form a tumor.A tumor is an abnormal mass. Cancer that occurs because of acquired mutations are not found in every cell in the body and they are not passed from parent to child.

Factors that causes these mutations include:

Germ line mutations:  

These are less common.A germ line mutations occurs in a sperm cell or egg cell.It passes directly from a parent to a child at the time of conception.As they embryo grows into a baby,the mutation from the initial sperm or egg cell is copied into every cell within the body.Because the mutation effects reproductive cells,it can pass generation to generation.Cancer caused by germ line mutations is called inherited cancer. it accounts for about 5% to 20% of all cancers.

Mutations and cancer:

A mutation may be harmful beneficial or neutral.This depends where in the gene the change occurs.Typically the body corrects most mutations.A single mutations will likely not cause cancer.

Types of genes like a cancer:

Many of the genes that contribute to cancer development fall into board categories.

Tumors suppressor genes:

These are protective genes. Normally they limit cell growth by:

Answer:

1.52 g of NaCl

Explanation:

We'll begin by calculating the number of mole of chlorine gas (Cl₂) that occupied 0.3 L at STP. This can be obtained as follow:

Recall: 1 mole of any gas occupy 22.4 L at STP.

1 mole of Cl₂ occupy 22.4 L at STP.

Therefore, Xmol of Cl₂ will occupy 0.3 L at STP i.e

Xmol of Cl₂ = 0.3 / 22.4

Xmol of Cl₂ = 0.013 mole

Thus, 0.013 mole of Cl₂ occupied 0.3 L at STP.

Next, we shall determine the number of mole of NaCl produced from the reaction.

Cl₂ + 2Na —> 2NaCl

From the balanced equation above,

1 mole of Cl₂ reacted to produce 2 moles of NaCl.

Therefore, 0.013 mole of Cl₂ will react to produce = 0.013 × 2 = 0.026 mole of NaCl.

Thus, 0.026 mole of NaCl is produced.

Finally, we shall determine the mass of the NaCl. This can be obtained as follow:

Mole of NaCl = 0.026 mol

Molar mass of NaCl = 23 + 35.5 = 58.5 g/mol

Mass of NaCl =?

Mole = mass /Molar mass

0.026 = mass of NaCl / 58.5

Cross multiply

Mass of NaCl = 0.026 × 58.5

Mass of NaCl = 1.52 g

Therefore, 1.52 g of NaCl were produced from the reaction

Answer:

Evaporation is very important in the cooling of surfaces. If we put a drop of methylated spirit on our hand the methylated spirit will soon evaporate and our hand feels cold. The molecules of methylated spirit get the energy they need from our hand, leaving the molecules of the hand with less energy and so colder.

The ethylated sprit starts to evaporate from our hand. Evaporation is an endothermic process thus, absorbs the heat energy from our hand make the surface cool.

An endothermic process is the one which absorbs energy from the surroundings to proceed. Thus, an endothermic process make the surroundings cool and make the reaction system hot.

The process which evolves heat energy is called an exothermic process. An exothermic reaction make the surroundings hot sometimes leads to explosion.

Evaporation is the process of conversion of a liquid substance into vapor form. This process needs energy to intake. Hence during evaporation, the heat energy is absorbed from the surroundings make there cool. This is just happening on our hand when sprit evaporates.

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Answer:

c2h4s

Explanation:

You can reduce s2 to s

Answer:

Q =  1379.4 J

Explanation:

Given data:

Mass of water = 22  g

Initial temperature = 18°C

Final temperature = 33°C

Heat absorbed = ?

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Specific heat capacity of water is 4.18 J/g. °C

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 33°C - 18 °C

ΔT =  15°C

Q = 522 g ×4.18 J/g.°C× 15°C

Q =  1379.4 J

Answer:

Kf being the depression of freezing point constant in the equation:

change in temperature = Kf * molality

Kb being the elevation of boiling point constant in the equation:

change in temperature = Kb * molality

the constant is variable for each solvent.

Explanation:

Answer:

b

Explanation:

the answere is b

Answer:

Percent yield = 87.5%

Explanation:

Given data:

Number of moles of Fe(NO₃)₃ = 2.5 mol

Number of moles of Na₂CO₃ = 3.6 mol

Actual yield of NaNO₃ = 6.3 mol

Percent yield of NaNO₃ = ?

Solution:

Chemical equation:

2Fe(NO₃)₃ + 3Na₂CO₃        →     Fe₂(CO₃)₃ + 6NaNO₃

now we will compare the moles of both reactant with NaNO₃.

                   Fe(NO₃)₃          :              NaNO₃

                       2                   :                  6

                     2.5                  :            6/2×2.5 = 7.5

                  Na₂CO₃             :              NaNO₃

                       3                   :                  6

                     3.6                  :            6/3×3.6 = 7.2

Theoretical yield of NaNO₃ is 7.2 mol.

Percent yield:

Percent yield = actual yield / theoretical yield ×100

Percent yield = 6.3 mol / 7.2mol ×100

Percent yield = 87.5%

Answer:

So, a cell, in easiest terms, is "the building blocks of life". Without cells, humans, plants, animals, and anything else that has a cell would not be able to survive. Cells are extremely important to our bodies. Whereas a Cell Membrane is an organelle inside a cell. The Cell Membrane's job is to provide protection for the cell, as well as deciding which substances can enter and exit the cell.

I hope this helps!

How to make super saturated solution?

An aqueous solution can be rendered supersaturated by first dissolving the solute in water at an elevated temperature using enough to give a concentration just under its solubility at that temperature. After the last of the solute crystals have dissolved the solution is cooled.

Answer:

By adding water i guess

Slower growth rate is common characteristic of developing countries. Therefore, the correct option is option A.

A sovereign state that is considered to be developing has a less developed industrial base with an HDI that is lower than other nations. This term is not generally accepted, though. Furthermore, there is no consensus on which nations fall into this category.

Although the phrase "low and middle-income country" (LMIC) is sometimes used synonymously, it only relates to the economies of the nations. In accordance with gross national income per capita, the World Bank divides the world's economy into four categories: high, upper-middle, lower-middle, as well as low income countries. Slower growth rate is common characteristic of developing countries.

Therefore, the correct option is option A.

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Answer:

Isotope N–14 = 99%

Isotope N–15 = 1%

Explanation:

Let isotope A be N-14

Let isotope B be N-15

From the question given above, the following data were obtained:

For isotope A (N-14):

Mass of A = 14

Abundance of A = A%

For isotope B (N-15):

Mass of B = 15

Abundance of B = (100 – A%)%

Atomic mass of nitrogen = 14.01 amu

Thus, we can obtain the relative abundances of the naturally occurring isotopes of nitrogen as illustrated below:

Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100]

14.01 = [(14 × A%)/100] + [(15 × (100 – A%)/100]

14.01 = 0.14A% + 0.15(100 – A%)

14.01 = 0.14A% + 15 – 0.15A%

Collect like terms

14.01 – 15 = 0.14A% – 0.15A%

– 0.99 = – 0.01A%

Divide both side by – 0.01

A% = – 0.99 / –0.01

A% = 99%

Abundance of B = (100 – A%)%

Abundance of B = (100 – 99)%

Abundance of B = 1%

Thus, the relative abundances of the naturally occurring isotopes of nitrogen are:

Isotope N–14 = 99%

Isotope N–15 = 1%

Answer:Long-term drug abuse changes areas in the brain that affect behavior, judgment, learning and memory

Explanation:

Answer:

6Br⁻ + XeO₃ + 6H⁺ → 3Br₂ + Xe + 3H₂O  

Explanation:

First, we need to write the half-reactions:

2Br⁻ → Br₂ + 2e⁻ Oxidation -Balanced yet-

XeO₃ →  Xe Reduction

To balance the reduction in acidic aqueous solution we need to add waters in the other side of the reaction as oxygens are present:

XeO₃ →  Xe + 3H₂O

And H⁺ as hydrogens from water we have:

XeO₃ + 6H⁺ →  Xe + 3H₂O

To balance the charge:

To cancel out the electrons of both half-reaction we need to multiply oxidation 3 times:

6Br⁻ → 3Br₂ + 6e⁻

XeO₃ + 6H⁺ + 6e⁻ →  Xe + 3H₂O  

And the balanced reaction in acidic aqueous solution is the sum of both half-reactions:

Answer:

Covalent bond

Explanation:

I am pretty sure this is the answer

Answer:

8.9 mph

Explanation:

Answer:

Valency is the combining power of an element.

There are two types of valency - Electrovalency and Covalency.

Hope it helps!<3