Answer:
48 this answer is wrong so don't
starting with calcium chloride describe how one can prepare calcium carbonate
I need help with this
Answer:
the answer is the last one , sorry if im wrong.
Explanation:
Two clear solutions are placed in separate beakers. The first solution has a pH = 4, and the pH of the second solution is unknown.
If the two solutions are mixed and the resulting solution has a pH = 7, describe the second solution.
A) The second solution has a higher pH level than the first solution. It has a
pH that is weaker but still neutralized the first solution. It also has a higher
concentration of hydronium ions compared to the first solution.
B) The pH of the second solution is higher than the pH of the first solution. It
is also acidic and, therefore, has a higher concentration of hydroxide ions
compared to the first solution.
C) The second solution has a basic pH level. It was strong enough to
neutralize the first solution. It also has a higher concentration of hydroxide
ions compared to the first solution.
D) The second solution has and equivalent number of hydroxide and
hydronium ions. It has a pH level that is higher (stronger) than the first
solution.
Answer:
C.
Explanation:
When the pH is 7 there is equal amount of H+ and OH so the solution added must be strong enough to nuetralize the acid. So option A is out B is wrong because adding a acidic solution to an acidic solution wont nuetralize it, D is wrong because if the 2 solution was already equal in both it would essentaly be water. ALthough water would raise the pH it would not nuetralize it to a even 7.
A 27 kg iron block initially at 375 C is quenched in an insulated tank that contains 130kg of water at 26 C. Assume the water that vaporizes during the process condenses back in the tank and the surroundings are at 12 C and 125 kPa. The specific heats of iron and water are 0.45 kJ/kgK and 4.18 kJ/kgK, respectively. a: Determine the final equilibrium temperature. b: Determine the entropy change of the combined system at the initial state. c: Determine the exergy of the combined system at the initial state. d: Determine the waste work potential during this process.
Solution :
a). Applying the energy balance,
[tex]$\Delta E_{sys}=E_{in}-E_{out}$[/tex]
[tex]$0=\Delta U$[/tex]
[tex]$0=(\Delta U)_{iron} + (\Delta U)_{water}$[/tex]
[tex]$0=[mc(T_f-T_i)_{iron}] + [mc(T_f-T_i)_{water}]$[/tex]
[tex]$0 = 27 \times 0.45 \times (T_f - 375) + 130 \times 4.18 \times (T_f-26)$[/tex]
[tex]$t_f=33.63^\circ C$[/tex]
b). The entropy change of iron.
[tex]$\Delta s_{iron} = mc \ln\left(\frac{T_f}{T_i} \right)$[/tex]
[tex]$ = 27 \times 0.45\ \ln\left(\frac{33.63 + 273}{375 + 273} \right)$[/tex]
= -9.09 kJ-K
Entropy change of water :
[tex]$\Delta s_{water} = mc \ \ln\left(\frac{T_f}{T_i} \right)$[/tex]
[tex]$ = 130 \times 4.18\ \ln\left(\frac{33.63 + 273}{26 + 273} \right)$[/tex]
= 10.76 kJ-K
So, the total entropy change during the process is :
[tex]$\Delta s_{tot} = \Delta s_{iron} + \Delta s_{water} $[/tex]
= -9.09 + 10.76
= 1.67 kJ-K
c). Exergy of the combined system at initial state,
[tex]$X=(U-U_{0}) - T_0(S-S_0)+P_0(V-V_0)$[/tex]
[tex]$X=mc (T-T_0) - T_0 \ mc \ \ln \left(\frac{T}{T_0} \right)+0$[/tex]
[tex]$X=mc\left((T-T_0)-T_0 \ ln \left(\frac{T}{T_0} \right)\right)$[/tex]
[tex]$X_{iron, i} = 27 \times 0.45\left(((375+273)-(12+273))-(12+273) \ln \frac{375+273}{12+273}\right)$[/tex]
[tex]$X_{iron, i} =63.94 \ kJ$[/tex]
[tex]$X_{water, i} = 130 \times 4.18\left(((26+273)-(12+273))-(12+273) \ln \frac{26+273}{12+273}\right)$[/tex]
[tex]$X_{water, i} =-13.22 \ kJ$[/tex]
Therefore, energy of the combined system at the initial state is
[tex]$X_{initial}=X_{iron,i} +X_{water, i}$[/tex]
= 63.94 -13.22
= 50.72 kJ
Similarly, Exergy of the combined system at initial state,
[tex]$X=(U_f-U_{0}) - T_0(S_f-S_0)+P_0(V_f-V_0)$[/tex]
[tex]$X=mc\left((T_f-T_0)-T_0 \ ln \left(\frac{T_f}{T_0} \right)\right)$[/tex]
[tex]$X_{iron, f} = 27 \times 0.45\left(((33.63+273)-(12+273))-(12+273) \ln \frac{33.63+273}{12+273}\right)$[/tex]
[tex]$X_{iron, f} = 216.39 \ kJ$[/tex]
[tex]$X_{water, f} = 130 \times 4.18\left(((33.63+273)-(12+273))-(12+273) \ln \frac{33.63+273}{12+273}\right)$[/tex]
[tex]$X_{water, f} =-9677.95\ kJ$[/tex]
Thus, energy or the combined system at the final state is :
[tex]$X_{final}=X_{iron,f} +X_{water, f$[/tex]
= 216.39 - 9677.95
= -9461.56 kJ
d). The wasted work
[tex]$X_{in} - X_{out}-X_{destroyed} = \Delta X_{sys}$[/tex]
[tex]$0-X_{destroyed} = $[/tex]
[tex]$X_{destroyed} = X_{initial} - X_{final}$[/tex]
= 50.72 + 9461.56
= 9512.22 kJ
А
A and B are forces acting on a falling object. Which
force, A or B, represents gravity in the diagram?
Force 1
is gravity because it attracts the ball
to the ground.
B
Ground
Answer:
Force B
Explanation:
Gravity pulls "down" :D
Hoped this helped!
Have a nice day!
why does water wet glass and not mercury
Explain how abiotic factors change within a community as a result of the
succession of vegetation.
1. What is the modern view of electrons in the quantum mechanical model?
Answer: An electron con only exist in a limited number of quantized energy levels.
Explanation:
Le Châtelier’s principle is applied in the bottling of carbonated soft drinks. You are probably familiar with the “hissing” or “popping” sound of opening of either an aluminum soda can or plastic bottle. This occurs by adding carbon dioxide to water to produce carbonic acid in a reversible reaction, which is shown below: H2O(l) + CO2(g) <-------------------> H2CO3(aq) As you may have known, these beverages are bottled under increased pressure, placing stress on the equilibrium. Following Le Châtelier’s principle, the system shifts to the right to reduce the stress, in response to the increase in pressure. When the bottle or can is opened, the pressure is reduced. This reaction favors the reactants, thus shifting the system to the left, and CO2 gas forms and comes out of the solution. Question # 8 :You open a can of Coca-Cola and you pour it into a glass with ice. You notice that the soda is very fizzy and quite effervescent. What do you think is responsible for this? Group of answer choices A. H2O formation under pressure. D. Release of H2O as a result of opening the can. B. H2CO3 formation under pressure. C. Release of CO2 as a result of opening the can.
Answer:
C. Release CO2 due to can opening
Explanation:
Le Châtelier’s principle states that when a reaction is at equillibrium and it is disturbed it will respond to return to equilibrium.
SO
H2O(l) + CO2(g) <-------------------> H2CO3(aq)
When you open a bottle of coke it is under pressure and not at equillibrium so it reacts by releasing the gas to reach equilibrium it can be seen in the equation above just that this is for club soda not coke, the idea applies though
HELP PLEASEUse the molar volume of a gas at SATP to determine the
following values at SATP:
(a) the amount of nitrogen in 44.8 L of pure gas
(b) the volume (in litres) of 4.8 mol of propane gas, C3H,(g)
(c) the mass of carbon dioxide in 34.6 L of carbon dioxide
gas, CO₂(g)
(d) the volume (in mL) of 1250 g of methane, CH₂(g)
(e) the amount of oxygen in 36.5 L of 02 gas
The most common example is the molar volume of a gas at standard temperature and pressure (STP), which is equal to 22.4 L for 1 mole of any ideal gas at 273.15 K and 1 atm of pressure.
What are the applications of the Ideal Gas Law- Molar Volume?Stoichiometry refers to the quantitative relationship between reactants and products. Calculating the quantities of reactants needed to make a given quantity of products, or the quantities of products resulting from a given quantity of reactants, is required in stoichiometric problems. Gas laws must be taken into account for the calculation if one or more reactants or products in a chemical reaction are gases. The findings of ideal gas law applications are often accurate to within 5%. We go over a few key ideas that are crucial for solving Stoichiometry Problems involving Gases in the sections below.
Stoichiometry and gas laws both rely on the mole notion as their foundation. A mole is an exact measurement of a substance. Based on the quantity of identities, a mole is a unit (i.e. atoms, molecules, ions, or particles). The number of identities in a mole of anything is equal to the number of atoms in exactly 12 grams of carbon-12, the most common isotope of carbon.
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Q1. Describe the term "Displacement reaction"
What is the [H+] if [OH-] = 1 x 10-5 M?
Manganese is a transition metal. Consider the isotope: Mn-53. How many protons are in an atom of Mn-53 if the atom has a charge of 5?
Answer:
25
Explanation:
Isotopes of an element are the same element with different mass numbers but the same atomic number or the number of protons.
we know that in a balanced atom
Number of electrons = Number of protons = Atomic number
Atomic number (z) of manganese = 25
For Mn+5, the number of protons remains the same = 25
However, the number of electrons on Mn+5 = 21
Answer: 25
Explanation:
0.0075mole of calcium trioxocrabonate IV is added to 0.015mole of a solution of hydrochloric acid .the volume of gas evolved at stp is
Answer:
1mole of gas at STP = 22.4dm3
0.0075 mole of CaCO3 = xdm3
cross multiply;
where 22.4dm3 = 22400cm3
x * 1 = 0.0075 * 22400 → 168cm3
the gas CO2 which evolved was gotten from CaCO3 so we use the number of moles of CaCO3 only
The following statements are either true or false. Read each sentences carefully, then write TRUE faLSE
1. A force cannot be seen
2. A force cannot be felt.
3. A force always causes things to move
When an object is at rest, no gravitational force is acting on it
5 Gravitational force pulls all things downward
5. Mass and weight are the same quantities
7. All objects on Earth have weight
8 Some forces are useful to people
9. Gravity makes it easy for a person to ride a bicycle up
10. Weight is measured in grams (R) and kilograms
1) T
2) F
3) F
4) F
5) T
6) F
7) T
8) T
9) F
10) ...T... grams are usually in lowercase g
How to solve this problem? I am stuck
The functional group of molecules as follows :
Molecule 1. is aldehyde and ketone, Molecule 2 is acid and thio, Molecule 3 is acid and amide, Molecule 4 is alcohol and ether, Molecule 5 is Alcohol and acid. The image attached below show the functional group and molecules are labeled.
What is polar compound ?The polar compounds are those compound having different positive and negative charge, therefore the bonding with atoms such as nitrogen, oxygen, or sulfur.
A buffer is a solution the can control the pH change along with the addition of an acidic or basic substance. It is able to neutralize small amounts of added acid or base, So it maintains the pH of the solution. This is important to maintain pH ranges.
Thus, Molecule 1. is aldehyde and ketone, Molecule 2 is acid and thio, Molecule 3 is acid and amide, Molecule 4 is alcohol and ether, Molecule 5 is Alcohol and acid.
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Neera and Tom dissolved different masses of salt in 500 cm³ of water.
They measured the temperature at which each salt solution boiled.
salt
solution
(They wrote down the variables that might affect the investigation.
temperature of the
mass of salt
laboratory
dissolved in water
boiling point of
salt solution
thermometer
volume of water
starting temperature
of the water
type of salt used
The variables that might affect the investigation while dissolving different masses of salt are temperature and mass of the salt.
In the provided investigation, what are the independent and dependent variables?A variable that changed during the inquiry is regarded as an independent variable and is called "mass of salt dissolved in water." While the investigation's dependent variable, "boiling point of salt solution," is a variable that was monitored.
What are variables in a laboratory?There are numerous things that can be changed to see how they affect other things. Variables are the changeable quantities. Any element, character trait, or condition that can exist in a variety of forms or concentrations is a variable. Independent, dependent, and controlled variables are the three types of variables that often make up an experiment.
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Neera and Tom dissolved different masses of salt in 500 cm3 of water.
They measured the temperature at which each salt solution boiled.
(a) They wrote down the variables that might affect the investigation.
temperature of the laboratorymass of salt dissolved in waterstarting temperature of the waterboiling point of salt solutionvolume of watertype of salt used(i) What is the independent variable (the variable they changed) in
their investigation?
(ii) What is the dependent variable (the variable they measured) in
their investigation?
(iii) Which variable above would affect the experiment the least?
Q)A certain mass of gas occupies a volume 2.5 L at 90atm. What pressure would the gas exert if it were placed in a 10 L container at the same temperatur?
Answer:
23 atm
Explanation:
Step 1: Given data
Initial volume (V₁): 2.5 LInitial pressure (P₁): 90 atmFinal volume (V₂): 10 LFinal pressure (P₂): ?Step 2: Calculate the final pressure of the gas
If we assume constant temperature and ideal behavior, we can calculate the final pressure of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
P₂ = P₁ × V₁ / V₂
P₂ = 90 atm × 2.5 L / 10 L = 23 atm
As expected, since the volume increased, the pressure decreased.
Why Zinc is not really considered as member of the transition metals?
The definition of a transition metal is that it must have an incompleted sub-level in one or more of its oxidation states. As zinc has a completed sub-level at all oxidative states, so it can't be considered a transition metal.
Pls help with question a and b.
a) 1 - Trigonal planar 2 - Trigonal planar
b) 1- Linear 2 - Tetrahedral 3 - Tetrahedral
c) 1 - Trigonal planar 2 - Tetrahedral
What are the shapes?We have to know that the shapes at the various carbon atoms and other atoms would depend on the number of the electron pairs and the hybridization of the atom.
We must have to note that the shape of the atom can be found on the basis of the valence shell electron pair repulsion theory which deals with the arrangement of that electrons around the outermost shell of the central atom.
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The graph represents the amount of energy in the
reactants and products of a chemical reaction.
If total energy is conserved, which statement
explains why the energy of the reactants does not
equal the energy of the products?
Energy
Energy of Energy of
Reactants Products
A.
The reaction is exothermic
B. The reaction is endothermic.
C. The reaction requires a catalyst.
D
The reaction has a low activation energy.
Answer: The correct answer is in an exothermic reaction the energy of the product is less than the energy of the reactants.
Explanation: got it
The energy of reactants is not equal to that of products as the reaction is an exothermic reaction.
What is an exothermic reaction?
An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.
In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.
Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.
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Calculate the molecular weight of chalk.Step by step
Answer:
100 g/mol
Explanation:
The chemical formula of chalk is CaCO3
So
1x Ca =40
1x C = 12
Ox 3 = 16
Meaning it has a molar mass of 100
A 6.8 L sample of gas is collected at a pressure of 0.91 atm. What will the Volume of the gas occupy at 1.0 atm if the temperature remains constant?
Answer:
Explanation:
V1*P1= V2*P2
6.8L*0.91atm=1.0atm*x
x=6.188 L
matching will give brainliest. if you can answer any it help
1. element with atomic number greater than 92.
2. helium nucleus with and atomic number or 2 and a mass of 4.
3. unit for measuring exposure to radiation.
4. changing of one element to another due to alpha or beta decay.
5. caused by the decay of an electron.
6. atoms of the same element with different numbers of neutron.
7. the initial isotope before decay.
a. rem
b. alpha particle
c. beta particle
d. trans uranium element
e. transmutation
f. isotope
g. parent nuclide
Explanation:
In natural radioactive decay, three common emissions occur. When these emissions were originally observed, scientists were unable to identify them as some already known particles and so named them:
alpha particles ( α )
beta particles (β)
gamma rays (γ)
These particles were named using the first three letters of the Greek alphabet. Some later time, alpha particles were identified as helium-4 nuclei, beta particles were identified as electrons, and gamma rays as a form of electromagnetic radiation like x-rays, except much higher in energy and even more dangerous to living systems.
Given: Mg3N2 + 3 K2O → 3 MgO + 2 K3N
If 14 moles of potassium oxide, K2O, reacts, how many grams of potassium nitride, K3N, will be made? Show work
Explanation:
14 moles of potassium oxide, K2O, reacts, how many grams of potassium nitride, K3N, will be made? Show work
the bond between br atoms in a br2 molecule is
Answer:
COVALENT
Explanation:
covalent and is formed by the sharing of two valence electrons.
4.
Ethanol has a specific heat of 2.44 (J/g.°C). The temperature of 34.4 g of ethanol increases
from 25 °C to 78.8 °C. How much Heat was absorbed?
Atoms bond by ______ electrons.
O gaining
O sharing
O losing
O all of the above
Students performed an investigation on how aluminum cans taken to a recyle center were able to be reused. They found out an aluminum can undergoes which type of change?
a physical change because the can is heated
a chemical change because new metal is formed
a physical change because the material remains the same
a chemical change because an old can is changed into a new can
Answer:
The correct answer is - a physical change because the material remains the same.
Explanation:
A chemical change is the change that results in the formation of the new element or the substance whereas the physical change remains the same material or substance even after the change.
The physical change can be a change in density, size, shape, or volume, and other properties. In the recycling of the aluminum can the material remain the same only shape or size of the aluminum change order to reuse.
Answer:
its D i promise
Explanation:
Can someone help me with this pls
Answer:
i think the correct answer is A