A student walks 15 km in 3 hours. What is the student’s average speed?

A :45 km/h
B :5 km/h
12 : km/h
18 : km/h

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.

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Answer:

Coffee

Explanation: When a liquid is warm the particles move faster

Answer:

60 g/ mol

Explanation:

Carbon, C 12

Hydrogen, H 1

Oxygen, O 16

Molar mass = 12+3+12+16+16+1 = 60 g/ mol

[tex]\boxed{\boxed{\pink{\bf \leadsto This \ is \ an \ example \ of \ Chemical \ change .}}}[/tex]

Reaction of sodium metal with water is a chemical change . Sodium reacts with water to form sodium hydroxide. This is also an example of exothermic reaction as heat is released in this process. Sodium reacts vigoursly with water , it even reacts with the moisture present in the air . So it is stored in kerosene oil .

The reaction of sodium with water is :-

[tex]\boxed{\red{ \bf \underset{\blue{Sodium}}{2Na} + \underset{\blue{Water}}{2H_2O} \longrightarrow \underset{\blue{Sodium\: Hydroxide}}{2Na(OH)}+ \underset{\blue{Hydrogen}}{H_2}}}[/tex].

The reaction of sodium metal with water is a chemical change, as a result formation of sodium hydroxide occurs.

The following points to be noted for the reaction of sodium with water:

Therefore, the reaction of sodium with water is a chemical change.

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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:

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:

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:

A highly positive ion was attracted to a membrane and their locations is explained in details.

Explanation:

1.

The Head of a lipid is hydrophilic (polar). This cover can be bearing negative or positive charges. This is that charge that creates the head hydrophilic(communicate with water(a polar molecule, including negative and positive unfair charges).

The tail is hydrophobic (non-polar). This part doesn't include any charge that enhances hydrophobic. (Does not combine with water.

Now a positive ion can be brought only to electron-rich stations. We cannot say that this situation is forever the hydrophilic part.

A dual bond is an electron-rich situation. So the ion will be drawn to the dual bond place of a lipid.

2.

A conveyor that needs energy is active transport.

3.

The use of a membrane is to stop the particles and ions from passing crosswise it openly. So through the membrane, in an active carrier, we require input energy to transfer molecules beyond it.

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: Electricity

Explanation: Electricity is the movement of matter. not matter itself

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:

b

Explanation:

the answere is b

Answer:

H20

Explanation:

Answer:

The answer is H20

Explanation:

Answer:

False

Explanation:

I got 100 on the test on edge

Answer:

This question appear incomplete

Explanation:

This question appear incomplete because of the absence of options. However, it seeks to differentiate between a scalar and a vector quantity. A scalar quantity is a quantity with just magnitude but no direction (example is mass) while a vector quantity is a quantity with both magnitude and direction. Thus, a quantity needs direction to complete it's description when such quantities is a vector quantity such as weight (which is the downward force/gravity acting on an object with relative mass). The mass is the magnitude while the gravity/downward force is the direction. It would just be a scalar quantity if it had just mass and no downward force (as in direction) acting on it.

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:

c2h4s

Explanation:

You can reduce s2 to s

Answer:

the answer is the second choice actual force

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:

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:

A. 21.47 atm

B. 0.4737 mol

C. 0.900moles of O2

1.200 moles of CO2

1.200 moles of H2O

2.400 mol of Ne that doesn't react.

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Therefore,  the total pressure in the cylinder is 21.4atm. Ideal gas is a hypothetical gas.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature. Vanderwaal gas behave as ideal gas at low pressure and high temperature.

Mathematically,

PV=nRT

where,

P = pressure=?

V= volume=7.80 L

n =number of moles=2.700 mol +0.600 mol +2.400 mol

                                =5.7moles

T =temperature = 358 K

R = Gas constant = 0.0821 L.atm/K.mol

substituting all the given values in the above equation, we get

P × 7.80 L =5.7moles× 0.0821 L.atm/K.mol × 358 K

On calculations, we get

P =21.4atm

Therefore,  the total pressure in the cylinder is 21.4atm.

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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:

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:

You are not at sea level.

Explanation:

Assuming empirical observation shows boiling point 'below' 100°C then one concludes boiling experiment is being conducted above sea level where air pressure is lower than sea level air pressure. Generally, it is accepted in most literature publications that atmospheric pressure decreases ~1-inch per 1000-ft increase in elevation.

By definition, the boiling point of a liquid occurs when the atmospheric pressure equals fluid vapor pressure. Thus, if experimentally a water sample  boils less than 100°C then one can only conclude the atmospheric pressure is lower than that needed to boil water at sea level atmospheric pressure; i.e., observed boiling point is at elevation greater than sea level.

One can calculate the boiling point of a liquid relative to sea level boiling point by using the Clausis-Clapeyron Equation.

ln(VP₂/VP₁) = ΔH(vap)/R(T₁ - T₂/T₁·T₂) solve for T₂ given Heat of Vaporization of water (ΔH(vap) = 28.2 Kj/mol) at specified temperature (T₁ at sea level = 273 Kelvin - standard) and R = 0.008314 Kj/mol-K).

Answer:

0.095 moles of O₂ are left over.

Explanation:

First of all, state the balanced reaction:

2NO + O₂ → 2NO₂

We determine moles of each reactant:

20.2 g . 1mol / 30g =  0.673 moles of NO

13.8g . 1mol / 32g = 0.431 moles of oxygen

Oxygen is the excess reactant. Let's see.

For 2 moles of NO I need 1 mol of O₂

Then, for 0.673 moles of NO I may use (0.673 .1) /2 = 0.336 moles

I have 0.431 moles of O₂ and I only need 0.336 mol. According to reaction, stoichiometry is 2:1.

In conclussion, the moles of excess reactant that will be left over:

0.431 - 0.336 = 0.095 moles

Answer:

Lymphocytes

Explanation:

Pathogens are particles that make you sick like bacteria, viruses, amoebas. Water is essential for life but that's for metabolism, not fighting off against infection or viruses.

Answer:

Lymphocytes

Explanation:

lymphocytes are a kind of white blood cell (WBC). Lymphocytes are cells of the immune system and help fight infection. Lymphocytes live in lymph nodes, but also in the bloodstream and all over the body. Lymphocytes come in two main types: B-cells and T-cells

Where as water is totally not white blood cells and pathogens are viruses and bacterium

Answer:

Valency is the combining power of an element.

There are two types of valency - Electrovalency and Covalency.

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Answer:

the answer is a true

Explanation:

Thiols, sulfides and disulfides have high solubility in water. This statement is true. Therefore, option A is correct.

Solubility refers to a substance's ability to form a solution with another substance, the solvent. The inability of the solute to form such a solution is referred to as insolubility.

Temperature, pressure, polarity, and molecular size are all factors that influence solubility. For most solids dissolved in liquid water, solubility increases with temperature. This is due to increased vibration or kinetic energy of the solute molecules at higher temperatures.

A rise in temperature stresses the equilibrium condition, causing it to shift to the right. Because the dissolving process consumes some of the heat, the stress is reduced. As a result, as the temperature rises, so does the solubility.

Thus, option A is correct.

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Answer:

B.

Explanation:

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

Answer:

2 is the answer your welcom