How much heat is required to change temperature of 2g of water from 34°C to 68°C? (Water has a specific heat of 4.18)
a) 852.7 joules
b) 284.2 joules
c) 2 joules
d) -284.2 joules

Answer:

The correct option is;

D. Petrol  > Alcohol > Kerosene oil > Water

Explanation:

The volatility of a liquid is a measure of how readily it evaporates or vaporizes such that a volatile liquid will evaporate and be present as a vapor at a given temperature or pressure than a less volatile liquid

The volatility of a liquid is directly related to the liquid's vapor pressure such that the higher the vapor the more volatile the liquid

The Reid vapor pressures of the given liquids are as follows;

Alcohol (Ethanol)= 17-55 kPa

Petrol = 53-60 kPa

Kerosene Oil= 6.8 kPa

The vapor pressure for water at 37.8°C = 6.6 kPa

Therefore, the correct order evaporation is as follows, starting from the highest vapor pressure to the lowest;

Petrol  > Alcohol >  Kerosene Oil > Water.

Answer:

iron

Explanation:

rust is an oxide of iron

Answer:

The answer is A.

Explanation:

When acid react with metal carbonate, it will form salt, water and carbon dioxide.

For example :

HCl + CaCO3 → CaCl + H2O + CO2

Answer:

I’ll help what’s the question

Explanation:

Answer:

Aight wats da question

Explanation:

Answer:

Mass and charge is conserved

Explanation:

According to the law of conservation of mass, matter is neither created or destroyed. With the exception of nuclear reactions where mass is converted to energy thereby leading to an apparent loss in mass, this law applies to chemical reactions.

A redox reaction is a type of chemical reaction which involves a transfer of electrons. In a redox reaction, the mass of reactant particles is conserved. Also, as electrons are transferred between atoms, one donates and the other accepts. The charge of atoms depends on this gain or loss of electrons. A gain of electrons reduced the charge of an atom whereas a loss of electrons increases the charge. This two processes occur concurrently, therefore, charge is also conserved.

Answer:

THE FREEZING POINT OF A WATER SOLUTION OF FRUCTOSE MADE BY DISSOLVING 92 g OF FRUCTOSE IN 202g OF WATER IS -4.70 ◦C

Explanation:

To calculate the freezing point of a water solution of fructose,

1. calculate the molar mass of Fructose

( 12 * 6 + 1*12 + 16*6) =72 + 12 +96 = 180 g/mol

2. calculate the number of moles of fructose in the solution

number of moles = mass / molar mass

n = 92 g / 180 g/mol

n = 0.511 moles.

3. calculate the molarity of the solution

molarity = moles / mass of water in kg

molarity = 0.5111 / 202 g /1000 g

molarity = 0.5111 / 0.202

molarity = 2.529 M

4. calculate the change in the freezing point of pure solvent and solution ΔTf

ΔTf = Kf * molarity of the solute

Kf = 1.86 ◦C/m for water

ΔTf = 1.86 * 2.529

ΔTf = 4.70 C

5. the freezing point is therefore

0.00 ◦C - 4.70 ◦C = -4.70 ◦C

Answer:

-4.7°C

Explanation:

In this question, we want to calculate the freezing point of the water solution of fructose.

We proceed as follows;

Firstly, we find the number of moles of the fructose using molar mass

Number of moles = mass/molar mass

mass is 92g , molar mass of fructose is 180g/mol

Number of moles = 92/180 = 0.51 moles

Next thing is to calculate the molality of the solution = number of moles of fructose/mass of water in kg = 0.51/(202/1000) = 0.51/0.202 = 2.525m

Now, we calculate the freezing point depression;

Δ[tex]T_{f}[/tex] = [tex]K_{f}[/tex] × m

where [tex]K_{f}[/tex] refers to the molal freezing point depression of the solvent = 1.86

Δ[tex]T_{f}[/tex] = 1.86 × 2.525 = 4.7 °C

Since the presence of impurities decrease freezing point and the normal freezing point of water is 0 °C, the freezing point of the solution is 0-4.7 = -4.7 °C

Answer:

If the weight of chemical is same so it represent that the experiment is valid.

Explanation:

If Bronwyn performed the same chemical reaction four times and she measure the weight of chemical with the help of electrical weight balance so if she find out the weight of the chemical that is produced during four experiments then we can say that the experiment is valid because the experiment was performed four times and that is enough for validation of the experiment.

Answer:

Explanation:

According to hooks law "provide the elastic limit of an elastic material is not exceeded the extension e is directly proportional to the applied force F"

[tex]F= ke[/tex]

where F= applied force

           k= spring constant

           e= extension

Given data

length of string l = 16cm

extension  e = 20-16= 4cm

applied force = 5N

we need t o first calculate the spring constant k

apply the formula

[tex]F= ke[/tex]

[tex]5=k*4\\k= \frac{5}{4} \\k= 1.25N/cm[/tex]

we can now calculate the extension of the string when supporting a 6N weight

[tex]F= ke\\6=1.25*e\\e= \frac{6}{1.25} \\e= 4.8cm[/tex]

The length of the string when supporting a 6N weight is

[tex]= length+ extension\\= 16+4.8\\= 20.8cm[/tex]

COMMENT :According to the analysis an extra  weight of 1N will cause add 0.8cm to the length of the string

Answer : The correct option is, (C) 3

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, [tex]CH_3Cl[/tex]

As we know that carbon has '4' valence electrons, hydrogen has '1' valence electron and chlorine has '7' valence electrons.

Therefore, the total number of valence electrons in [tex]CH_3Cl[/tex] = 4 + 3(1) + 7 = 14

According to Lewis-dot structure, there are 8 number of bonding electrons and 6 number of non-bonding electrons.

Hence, the number of lone pairs of electrons present on chlorine are, 3.

Answer:

Melting point

Explanation:

Answer:

Melting point

Explanation:

When a solid turns into a liquid, it is melting.  Therefore, it is the melting point.

Answer: C

Explanation:

For this problem, we would use Charles's Law. We fill in what we are given and solve.

Charles's Law: [tex]\frac{V_{1} }{T_{1} } =\frac{V_{2} }{T_{2} }[/tex]

[tex]\frac{10 L}{5K} =\frac{4.00L}{T_{2} }[/tex]

[tex]10T_{2}= 20[/tex]

[tex]T_{2}=2K[/tex]

Answer:

bromine (Br)

Explanation: Iron enters into a reaction with substances of different classes, and interacts with oxygen, carbon, phosphorus, halogens (bromine, iodine, fluorine and chlorine), and also nitrogen. These are not all the reactions of iron – this metal reacts with many elements.

Answer:

We can't see the question. Can you upload a picture of it or write the question in the comments

KK

Which chemistry question?

Answer:

C6H120

Explanation:

atom ratio= 1:2:1 even though it has 6 carbon.

mass ratio=6:1:8

is this what you wanted/needed?

Answer: The molarity is 0.25 M

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]CO_2[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{11g}{44g/mol}=0.25mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]Molarity=\frac{0.25\times 1000}{1000ml}[/tex]

[tex]Molarity=0.25M[/tex]

Therefore, the molarity is 0.25 M

Answer:

-the number of outer electrons

Explanation:

Outer electrons are referred to as valence electrons and they are typically what determines the property of an elements such as their reactivity.

For eg, Na (sodium) has 1 valence electron and it really wants to give it aways so it can return back to octet rule (having 8 electrons in outershell) to become stable. So when you put sodium in water (you can watch videos of it) it literally blows because of high reactivity.

Answer:

The new temperature is 527.15 ºC.

Explanation:

Charles’s law states that the volume of a fixed  amount of gas maintained at constant pressure is directly proportional to the absolute  temperature of the gas (the absolute temperature is the Kelvin temperature).

We need to calculate the temperature after the expansion, that is T₂. For that, we use Charles' law:

[tex] V₁ ÷ T₁ = V₂ ÷ T₂ [/tex]

Because we have to use the absolute temperature, we convert ºC to K adding 273.15:

T₁ = 127 ºC + 273.15 ºC = 400.15 K

[tex] T₂ = V₂ × T₁ ÷ V₁ [/tex]

[tex] T₂ = 20. 0 L × 400.15 K ÷ 10.0 L [/tex]

T₂ = 800.3 K

We substract 273.15 to the result to convert it back to ºC:

T₂ = 800.3 - 273.15  = 527.15 ºC.

Answer:

B. The molecules collide less frequently.

Explanation:

When the pressure of a gas is lowered, the molecules collide less frequently and the correct option is option B.

Pressure of a gas is a measure of the force exerted by gas molecules on the walls of the container in which the gas is contained. It is a result of the random and continuous collisions of gas molecules with the container surface.

When the pressure of a gas is lowered, it means that the force exerted by the gas molecules on the container walls decreases. This can occur due to a decrease in the number of gas molecules or a decrease in their average kinetic energy, resulting in less frequent and less forceful collisions with the container.

Lowering the pressure of a gas does not necessarily imply an increase in the number of gas molecules or a decrease in their volume.

Thus, the ideal selection is option B.

Learn more about Pressure of gas, here:

https://brainly.com/question/31525061

#SPJ6

Answer:

2 moles of sugar in 1,000g of water

Answer: thermal equilibrium

Explanation: the temperature increased only when all of the water was in one phase.

Answer:

Electrolytes are salts or molecules that ionize completely in solution. As a result, electrolyte solutions readily conduct electricity.

Nonelectrolytes do not dissociate into ions in solution; nonelectrolyte solutions do not, therefore, conduct electricity.

nonelectrolyteA substance that does not dissociate into ions when in solution.

solutionA homogeneous mixture, which may be a liquid, gas, or solid, formed by dissolving one or more substances.

solute Any substance that is dissolved in a liquid solvent to create a solution.

electrolyte A substance that dissociates into ions when in solution.

saltAn ionic compound composed of cations and anions that are held together by electrostatic attraction.

when an ionizable solute dissociates, the resulting solution can conduct electricity. Therefore, compounds that readily form ions in solution are known as strong electrolytes. (By this reasoning, all strong acids and strong bases are strong electrolytes.)

By contrast, if a compound dissociates to a small extent, the solution will be a weak conductor of electricity; a compound that only dissociates weakly, therefore, is known as a weak electrolyte.

A strong electrolyte will completely dissociate into its component ions in solution; a weak electrolyte, on the other hand, will remain mostly undissociated in solution. An example of a weak electrolyte is acetic acid, which is also a weak acid.

Nonelectrolytes are compounds that do not ionize at all in solution.

Answer:

The combustion will release -3,321 KJ/mol of energy

Explanation:

What we need to do here is to first calculate the number of moles of methane burnt.

Mathematically, the number of moles of methane burnt = mass of methane/molar mass of methane

Molar mass of methane = 16g /mol

Thus the

number of moles will be ;

59.7/16 = 3.73 moles

Now, 1 mole of methane produces -890 KJ/mol if energy

Then the energy produced by by 3.73 moles of methane would be 3.73 * 890 = -3,320.8125

which is approximately -3,321 KJ/mol

Kindly note that the amount of heat is negative because it is an exothermic reaction

Answer:

Explanation:

The innate immune system is a defense system with which we are all born and which protects us at all times against all antigens, prevents harmful external bodies from entering our body.

The acquired immune system is the second line of defense and develops by exposing itself to various antigens, building a defense against it when the innate system cannot fight the invader.

Answer:

Part A. The Innate immune system

Part B. The adaptive (or active) immune system

Explanation:

The immune system refers to the organs, tissues cells and proteins which work together to protect the body from harmful invaders that cause disease such as micro-organisms like viruses, bacteria, etc.

Organs and tissues that form part of the immune system include the thymus and bone marrow, lymph nodes and vessels, spleen, and skin.

The main immune cells are the white blood cells, also called leukocytes. Some types of white blood cells, called phagocytes engulf invading organisms. Others called lymphocytes  help the body remember the invaders and destroy them.  The two kinds of lymphocytes are B lymphocytes and T lymphocytes, whose name depend on where they mature. Lymphocytes start their life in the bone marrow and either stay there and mature into B cells, or go to the thymus gland to mature into T cells.

The immune system consists of two main parts or system.

Answer:

B. Beryllium

Explanation:

because the  trend of ionization is going up a group it increases, as going across a period it deceases. beryllium being closes to the hist point in the periodic table it has the highest ionization energy. hope this helps.  

Answer: B. Beryllium

Explanation: Apex

Answer:

Approximately [tex]0.20\; \rm L[/tex].

Explanation:

Convert the temperature of this gas to absolute temperature:

[tex]T = 25\; \rm ^\circ C \approx (25 + 273.15)\; \rm K = 298.15\; \rm K[/tex].

Let [tex]P[/tex] and [tex]V[/tex] represent the pressure and volume of this gas, respectively. Let [tex]n[/tex] represent the number of gas particles in this gas. Let [tex]R[/tex] represent the ideal gas constant. By the ideal gas law:

[tex]P \cdot V = n \cdot R \cdot T[/tex].

For this question:

Look up the ideal gas constant [tex]R[/tex] that takes [tex]\rm atm[/tex] as the unit for pressure:

[tex]R \approx 0.082057\; \rm L \cdot atm \cdot K^{-1}\cdot mol^{-1}[/tex].

This question is asking for [tex]V[/tex], the volume of this gas. Rearrange the ideal gas equation and solve for [tex]V[/tex]:

[tex]\begin{aligned} V &= \frac{n \cdot R \cdot T}{P} \\ &\approx \frac{0.00831\; \rm mol\times 0.0082057\; \rm L \cdot atm \cdot K^{-1}\cdot mol^{-1}\cdot 298.15\; \rm K}{1.01\; \rm atm} \\ &\approx 0.0020\; \rm L\end{aligned}[/tex].