25% While standing in line, a student notices that some students are really tall, some are approximately her height, and others are very short. From her observations, what could be a logical inference for the variations in height? A The tall students are taking growth steroids. B The short students are not eating the proper foods. с The height of the students is inherited from their parents. D The height of the students cannot be determined from the observations. 9 > E​

Answer:

Answers are given below

Explanation:

Significant figures:

When we add or subtract the values the number of significant figures after decimal in result must be equal to the given measurement having less number of decimal places.

b) 5.45 -2.3

3.2

d) 14.98 + 27,340 + 84.7593

27439.74

When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value.

a) 628 × 342

214776

we will round off this value into 3 significant figures.

215000

c) 28.0/13.483

2.08

Answer:

[tex]CO3^{2-}[/tex] + [tex]2H3O^{+}[/tex] => [tex]2H2O[/tex] + [tex]CO2[/tex]

Explanation:

Nitric acid reacts with sodium carbonate to form sodium nitrate, carbon dioxide and water.

Sodium carbonate + nitric acid  => sodium nitrate + water + carbon dioxide

2HNO3  +  Na2O3  => 2NaNO3 + CO2 + H2O

So the net ionic equation is as follows:

[tex]CO3^{2-}[/tex] + [tex]2H3O^{+}[/tex] => [tex]2H2O[/tex] + [tex]CO2[/tex]

The sodium ion and the nitrate ions are not involved in the net equation because they are not changed in the reaction.

Answer:

what does it say its blurry

Explanation:  

Answer: b. False

Explanation:

The more energetic molecules move to a gas, spread out, and form bubbles when heating happens. When exposed to heat, many of the chemicals used in the laboratory are volatile and harmful (fire).

So leaving a material that you heat for even a second can be very hazardous and negligent.

Answer:

C

Explanation:

All thing in option c is flammable

Answer:

D

Explanation:

Answer:

b

Explanation:

Both ionic and covalent bonds when it has dissolved into water it will become ionic compound but when it was in gas situation it was covalent compound.

Answer:

Molarity = 0.27 M

Explanation:

Given data:

Volume of solution = 820 mL (820/1000 = 0.82L)

Mass of KI = 36.52 g

Molarity of solution = ?

Solution:

Number of moles of KI:

Number of moles = mass/molar mass

Number of moles = 36.52 g/ 166 g/mol

Number of moles = 0.22 mol

Molarity = number of moles / volume in L

Molarity = 0.22 mol / 0.82 L

Molarity = 0.27 M

Answer:

I can answer 1, lqva is magma outside of the volcano

Answer:

C. Cutting your hair

Explanation:

A physical change is one of the two types of changes in nature (the other being chemical change). A physical change does not affect the chemical composition of the substance(s) involved.

In this case, "CUTTING ONE'S HAIR" is an example of physical change because it involves the removal of the hair without altering the chemical composition of the hair. However, other examples given in the options of this question like digestion of food, getting a suntan (change in skin coloration), and growth in height all involve a change in the chemical nature of the parts involved, hence, they are examples of chemical changes.

Answer:

Eight

Explanation:

The L shell only holds eight electrons.

8

The L shell can only holds eight electrons

Answer:

Ionic compounds generally form between elements that are metals and elements that are nonmetals. For example, the metal calcium (Ca) and the nonmetal chlorine (Cl) form the ionic compound calcium chloride (CaCl2). In this compound, there are two negative chloride ions for each positive calcium ion

Answer:

c. the major gases that make up only the troposphere

Explanation:

Oxygen (O2) and nitrogen (N2) are the major gases that make up only the troposphere because both oxygen and nitrogen are heavy gases which is present at lower height so it comes under the troposphere layer while on the other hand, ozone gas that act as a filter for harmful radiation of the sun is present in the stratosphere which is present next to troposphere layer of atmosphere.

Answer:

It produces magnesium oxide and hydrogen gas.

Explanation:

When magnesium burns with steam it produces magnesium oxide which is white in color and hydrogen gas. When magnesium burns, it mixes with the oxygen present in the air produces magnesium oxide in powder form. Magnesium react with oxygen by giving two electrons present in its valance shells while the oxygen needs two electron for completing their valance shell and becomes stable.

Explanation:

physical properties of water

Water is a colourless and tasteless liquid. The molecules of water have extensive hydrogen bonds resulting in unusual properties in the condensed form. This also leads to high melting and boiling points. As compared to other liquids, water has a higher specific heat, thermal conductivity, surface tension, dipole moment, etc. These properties form the reason for its significance in the biosphere. Water is an excellent solvent and therefore it helps in the transportation of ions and molecules required for metabolism. It has a high latent heat of vaporization which helps in the regulation of body temperature.

______________________________________

Chemical properties of water

Water reacts with a lot of substances to form different compounds. Some significant reactions are as follows:

Amphoteric nature:

Water can act as both acid and base, which means that it is amphoteric in nature.

Example:

Acidic Behaviour: H2O(l)+NH3(aq) ⇌ H3O+(aq)+NH+4(aq)

Basic Behavior: H2O(l)+H2S(aq) ⇌ H3O+(aq)+HS−(aq)

Redox reactions:

Electropositive elements reduce water to hydrogen molecule. Thus, water is a great source of hydrogen. Let us see an example in this case:

2H2O(l)+2Na(s)→2NaOH(aq)+H2(g)

During the process of photosynthesis, water is oxidized to O2. As water can be oxidized and reduced, it is very useful in redox reactions.

Hydrolysis reaction

Water has a very strong hydrating tendency due to its dielectric constant. It dissolves many ionic compounds. Some covalent and ionic compounds can be hydrolyzed in water

__________________________________

Water is so critical for human life Because...

Water’s extensive capability to dissolve a variety of molecules has earned it the designation of “universal solvent,” and it is this ability that makes water such an invaluable life-sustaining force. On a biological level, water’s role as a solvent helps cells transport and use substances like oxygen or nutrients. Water-based solutions like blood help carry molecules to the necessary locations. Thus, water’s role as a solvent facilitates the transport of molecules like oxygen for respiration and has a major impact on the ability of drugs to reach their targets in the body.

Answer:

your answer is flammability

They are non-renewable resources that formed when prehistoric plants and animals died and were gradually buried by layers of rock.

Answer:

The bubble goes into the atmosphere.

Explanation:

All the dissolved air evaporated from the water when there is 1 atmospheric pressure for a long time because the air is dissolved with high pressure so when the pressure is removed from the gas present in water. The bubble go away from the water solution due to more kinetic energy present in it as compared to lower atmospheric pressure.

Answer:

12C + 14H₂ + O₂ = 2C₆H₁₃OH .

Explanation:

2,3-dimethyl-1-butanol  

= CH₃-CH(CH₃)-CH(CH₃)-CH₂OH.

Molecular formula = C₆H₁₃OH .

= C₆H₁₄O

12C + 14H₂ + O₂ = 2C₆H₁₃OH .

Answer:

Gravity, Inertia, and Velocity ( I decided to use three)

Explanation:

Gravity is the primary force that controls orbit and gravity works with inertia along with velocity.

Gravity, Inertia, and Velocity ( I decided to use three)

Explanation:

Gravity is the primary force that controls orbit and gravity works with inertia along with velocity.

Answer:

C. activates compounds for some reactions by transferring a phosphate group.

Explanation:

Adenosine triphosphate, also known as ATP, is an energy carrier molecule used by the cells of living organisms to carry out their cellular function. ATP has the peculiar ability to store and release energy needed to do work. This energy is stored when a phosphate molecule is added to ADP to form ATP while it is released when the last phosphate group is removed to form ADP.

ATP supplies energy to compounds by transferring one of its phosphate molecules to it in a process called PHOSPHORYLATION. This transfer causes the compound to be activated for the cellular process it is about to undergo.

This question is incomplete, the complete question is;

The equilibrium constant, Kc, for the following reaction is 7.00×10-5 at 673 K. NH4I(s) ---> NH3(g) + HI(g) Calculate the equilibrium concentration of HI when 0.343 moles of NH4I(s) are introduced into a 1.00 L vessel at 673 K

Answer:

the equilibrium concentration of HI is 1.302 × 10⁻⁵ M

Explanation:

Given that;

kc = 7.00 × 10⁻⁵ at 673 K

equilibrium concentration of HI = ?

when 0.343 moles of NH4I(s) are introduced into a 1.00 L vessel at 673 K

Molarity of NH4I = 0.343 / 1.00 = 0.343 M

NH4I(s) -----------------> NH3(g) + HI(g)

0.343                             0           0   ------> Initial

(0.343 - x)                        x            x   -------> equilibrium

we know that; solid does not take part in equilibrium constant expression

so

KC = [NH3] [HI] / NH4I

we substitute

7.00 × 10⁻⁵ = x² / (0.343 - x)  

0.00007 (0.343 - x) = x²

0.00002401 - 0.00007x = x²

x² + 0.00007x - 0.00002401 = 0

using; x = -b±√(b² - 4ac) / 2a

we substitute

x = -0.00007 ± √((0.00007)² - 4×1×-0.00002401) / 2×1

x = [-0.00007 ± √( 4.9×10⁻⁹ + 9.604×10⁻⁵)] / 2

x = [-0.00007 ± 0.00009604] / 2

Acceptable value of x = [-0.00007 + 0.00009604] / 2

x = 0.00002604 /2

x = 0.00001302 ≈ 1.302 × 10⁻⁵ M

therefore the equilibrium concentration of HI is 1.302 × 10⁻⁵ M

Answer:

Half-life of 150 years are those year that a radioactive element take to disintegrate to a half of it's original value.

I don't have graphical software

Answer:

B. Nitrogen

Explanation:

Hope this helps :)

The answer is nitrogen gas.

Answer:

5 km/h

Explanation:

divide the hours to the distance

Answer:

0.05 M

Explanation:

Mass of benzoic acid= 0.158g

Volume of benzoic acid= 100 mL

Volume of sodium hydroxide = 27.84mL

Molar mass of benzoic acid= 122g/mol

Number of moles of benzoic acid= 0.158g/122g/mol= 1.3 × 10^-3 moles

C= no of moles/volume

C= 1.3 × 10^-3 moles × 1000/100

C= 0.013M

So;

Volume of acid VA = 100mL

Concentration of acid CA= 0.013M

Volume of Base VB = 27.84mL

Concentration of Base CB= ???

Number of moles of acid NA =1

Number of moles of Base NB= 1

From;

CAVA/CBVB= NA/NB

CAVANB= CBVBNA

CB= CAVANB/VBNA

CB= 0.013 × 100 × 1/27.84 × 1

CB= 0.05 M

The molecular weight of unknown gas : 23.46 g/mol

Given

A vessel contains 10% of oxygen and 90% of an unknown gas.

diffuses rate of mixed gas = 86 s

diffuses rate of O₂ = 75 s

Required

the molecular weight of unknown gas (M)

Solution

The molecular weight of mixed gas :(M O₂=32 g/mol)

[tex]\tt 0.1\times 32+0.9\times M=3.2+0.9M[/tex]

Graham's Law :

[tex]\tt \dfrac{r_{O_2}}{r_{mixed~gas}}=\sqrt{\dfrac{M_{mixed}}{M_{O_2}} }\\\\\dfrac{75}{86}=\sqrt{\dfrac{3.2+0.9M}{32} }\\\\0.76=\dfrac{3.2+0.9M}{32}\\\\24.32=3.2+0.9M\\\\21.12=0.9M\rightarrow M=23.46~g/mol[/tex]

Answer:

No, ΔE does not always equal zero because it refers to the systems internal energy, which is affected by heat and work

Explanation:

According to the first law of thermodynamics, energy is neither created nor destroyed. This implies that the total energy of a system is always a constant.

So, according to the first law of thermodynamics we have that ΔE = q + w. This means that the value of  ΔE depends on q (heat) and  w(work). Hence ΔE is not always zero since it depends on the respective values of q and w.