Answer:
c = 0.38 j/g.°C
Explanation:
Given data:
Heat absorbed by copper = 10 j
Mass of copper = 30 g
Initial temperature = 18.20°C
Final temperature = 19.07°C
Specific heat capacity of copper = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
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 = 19.07°C -18.20°C
ΔT = 0.87 °C
10 J = 30 g×c×0.87 °C
10 J = 26.1 g.°C×c
c = 10 J /26.1 g.°C
c = 0.38 j/g.°C
Which is the best example and explanation that a physical change has occurred?
fireworks exploding, because energy is released as light and heat
gasoline burning, because it forms water vapor and carbon dioxide
O crushing an ice cube, because the chemical structure of the ice cube is changed
dicing potatoes, because the molecules are separated but remain the same substance
dicing potatoes, because the molecules are separated but remain the same substance
Answer:
For the people wondering, yes, dicing potatoes is the correct answer. Because a new substance has not formed.
Complete the balanced molecular chemical equation for the reaction below.
If no reaction occurs, write NR after the reaction arrow.
Cu2SO4(aq) + Li3PO4(aq)
Answer:
Following are the complete balance of the given equation:
Explanation:
Given equation:
[tex]Cu_2SO_4(aq) + Li_3PO_4(aq)[/tex]
[tex]Cu_2So4\ (aq)+Li_3Po_4 \(aq) \longrightarrow Cu_3(Po_4)\ (aq)+Li_2So_4 \ (aq)[/tex]
After Balancing the equation:
[tex]3 Cu_2So4\ (aq)+ 2 Li_3Po_4\ (aq) \longrightarrow 2 Cu_3(Po_4)\ (aq)+ 3Li_2So_4 \ (aq)[/tex]
In the above equation, when the 3 mol Copper sulfate reacts with 2 mol lithium phosphate , it will produce 2 mol Copper phosphate and 3 mol Lithium sulfate .
What forces cause mechanical weathering? Choose more than one
answer.
Answer:
mineral crystal growth
acid rain
carbonic acid
Answer:
Mineral crystal growth, Acid rain, Carbonic acid
Determine the density of CO2 gas at STP
Answer:
the density of CO2 gas at STP is 1.96 g/l.
Which statement best describes why a chemical property change is different from a physical change?
A. A chemical change results in a different state of matter; and a physical change results in a new substance being formed.
B. A chemical change results in a new substance being formed; whereas, a physical change will result in a different state of matter.
C. A chemical change is used by scientists to create new substances, and a physical change happens naturally.
D. A chemical change is used to identify characteristics of a substance, and a physical change identifies the behavior of a substance when in a reaction.
Answer:
B
Explanation:
a chemical change is making a new substance and physical change with a result in a different state of matter:)
Which of the following statements is true about covalent bonds?
Valence Electrons are shared in order to achieve the bond
O Covalent bonds form when the nuclei of atoms attract each other
O Covalent Bonds all have the same bond length no matter what atoms are in the
bond
Transferring of electrons from one atom to another creates the bond
Answer:
the answer is "Transferring of electrons from one atom to another creates the bond"
Explanation:
The statement which is true about covalent bonds is that the valence
electrons are shared in order to achieve the bond.
Covalent bonds involves the atoms of two elements sharing electrons in
order to achieve a stable configuration. The electrons which are shared are
those at the outermost layer of the shell and they are called valence
electrons.
These bonds help in the formation of new compounds such as water which
is formed from the covalent bonding between hydrogen and oxygen.
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A gaseous compound is placed in a rigid container of volume 10.0 L at temperature 300.0 K and at pressure 1.0 atm. The container is placed in an evacuated chamber and a small hole of area 2.65 mm2 is made in one of the container walls. It takes 1.00 minutes for the gas pressure in the container to fall to half of its original value. Determine the molar mass of the gas.
A collection of the same kind of cells working together to do the same job
Answer:
A group of cells doing the same job forms a tissue. A group of tissues working together forms an organ. Organs work in groups, too. A group of organs doing the same job is called a system.
Explanation:
Write the molecular, ionic, and net ionic equations for the reaction of Sr(NO3)2(aq) and Li2SO4(aq).
Answer:
Molecular: [tex]Sr(NO_3)_2(aq) +Li_2SO_4(aq)\rightarrow SrSO_4(s)+2LiNO_3(aq)[/tex]
Ionic: [tex]Sr^{2+}(aq)+2NO_3^-(aq) +2Li^{2+}(aq)+SO_4(aq)^{2-}\rightarrow SrSO_4(s)+2Li^+(aq)+2NO_3^-(aq)[/tex]Net ionic: [tex]Sr^{2}(aq)+SO_4(aq)^{2-}\rightarrow SrSO_4(s)[/tex]
Explanation:
Hello!
In this case, since the molecular, ionic and net ionic equations show the complete molecules, ions and resulting ions respectively, for the reaction between strontium nitrate and lithium sulfate, we can notice the formation of solid strontium sulfate and lithium nitrate as shown below:
[tex]Sr(NO_3)_2(aq) +Li_2SO_4(aq)\rightarrow SrSO_4(s)+2LiNO_3(aq)[/tex]
Which is the molecular equation showing both reactants and products as molecules. Then, the ionic equation shows all the reactants and products as ions, considering that aqueous solutions dissociate whereas solid, liquid and gaseous molecules do not, therefore, we obtain:
[tex]Sr^{2+}(aq)+2NO_3^-(aq) +2Li^{2+}(aq)+SO_4(aq)^{2-}\rightarrow SrSO_4(s)+2Li^+(aq)+2NO_3^-(aq)[/tex]
Finally, for the net ionic equation, we cancel out the spectator ions, which are those at both reactants and products:
[tex]Sr^{2+}(aq)+SO_4(aq)^{2-}\rightarrow SrSO_4(s)[/tex]
Best regards!
A further explanation is below.
Given:
[tex]Sr(NO_3)_2 (aq)[/tex] (Strontium nitrate)[tex]L1_2SO_4 (aq)[/tex] (Lithium sulfate)Strontium nitrate reacts with Lithium sulfate just to produce Strontium sulfate ([tex]Sr(NO_3)_2[/tex]) and Lithium nitrate ([tex]Li NO_3[/tex]).
The molecular equation will be:
→ [tex]Sr(NO_3)_2(aq) +Li_2SO_4(aq) \rightarrow SrSO_4 (s) +2LiNO_3 (aq)[/tex]
The complete ionic equation will be:
→ [tex]Sr^{2+} (aq) +2NO_3^- (aq) +2Li^+ (aq)+ SO_4^{2-} (aq) \rightarrow SrSO_4 (s)+2Li^+ (aq) +2NO_3^- (aq)[/tex]
By removing the uncharged ions from equation's will be:
Spectator ion:
→ [tex]2Li^+ (aq), 2NO_3^- (aq)[/tex]
Net ionic equation will be:
→ [tex]Sr^{2+}(aq)+SO_4^{2-} (aq) \rightarrow SrSO_4 (s)[/tex]
Thus the response above is right.
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How many atoms are in 80.7 g of pure aluminum?
Answer:
Like Roman said Avogadro's number is the key to your problem. The value that you'll use on paper is 6.022x10^23. Luckily in our case a mol specifically refers to the amount of atoms. Its a weird concept but 1.97 mol of Aluminum is the exact same amount of atoms as say helium. The only differences lay in the total mass of the sample.
According to the following reaction, how many grams of water are necessary to form 0.705 moles zinc hydroxide?
zinc oxide (s) + water (1) — zinc hydroxide (aq)
grams water
Answer:
12.69g
Explanation:
as you see in the equation the number of moles for zinc hydroxide is same the water so,
0.705=mass\18mol g^-1
mass of water = 12.69g
hope is helpful
How many moles of ion are in 2L of a 3M solution?
What are three ways that we can identify when a chemical reaction is occurring?
The energy level diagram shown below represents a fictional gas. What is the energy of a photon that would move an electron from level 2 to level 5?
A. 5.8 eV
B. 4.8 eV
C. 4.2 eV
D. 2.65 eV
The energy of a photon that would move an electron from level 2 to level 5 : B. 4.8 eV
Further explanationThe electron energy at the nth shell can be formulated:
En = -Rh / n²Rh = constant 2.179.10⁻¹⁸ J
So the electron transfer energy (ΔE)
ΔE = E final- E initial
energy at n=2(level 2) = -5.3 eV
energy at n=5(level 5) = -0.5 eV
So the energy absorbed :
[tex]\tt \Delta E=-0.5-(-5.3)=-0.5+5.3=4.8`eV[/tex]
The energy required to move an electron from level 2 to level 5 is 4.8 eV.
According to the Bohr model of the atom, an electron moves from a lower to a higher energy level when it absorbs energy. The same energy is released when the atom returns to ground state.
When an electron from level 2 to level 5, the energy of the photon required is;
ΔE = E5 - E2 = -0.5eV - (-5.3eV)
ΔE = 4.8eV
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Of the following elements, which one has the lowest first ionization energy?
boron carbon aluminum silicon
Answer:
Boron
Explanation:
Because it has a complete 2s orbital and therefore, an increased shielding of the 2s orbital will reduce the ionisation energy.
An egg sinks in fresh water but it floats on salty water.why?
Balance the following equations ___Fe + __O2= ___Fe3O4
1. 2Al(s) + 3H2SO4(aq) → Al2(SO4)3(aq) + 3H2(g) a. Determine the volume (mL) of 15.0 M sulfuric acid needed to react with 45.0 g of aluminum to produce aluminum sulfate. b. Determine the % yield if 112 g of aluminum sulfate is produced under the above conditions.
Answer:
a. 167 mL b. 39.27 %
Explanation:
a. From the chemical equation. 2 mole of Al reacts with 3 mole H₂SO₄ to produce 1 mol Al₂(SO₄)₃.
Now, we calculate the number of moles of Al in 45.0 g Al.
We know number of moles, n = m/M where m = mass of Al = 45.0 g and M = molar mass of Al = 26.98 g/mol.
So n = 45.0 g/26.98 g/mol = 1.668 mol
Since 2 mole of Al reacts with 3 mole H₂SO₄, then 1.668 mole of Al reacts with x mole H₂SO₄. So, x = 3 × 1.668/2 mol = 2.5 mol
So, we have 2.5 mol H₂SO₄.
Now number of moles of H₂SO₄, n = CV where C = concentration of H₂SO₄ = 15.0 M = 15.0 mol/L and V = volume of H₂SO₄.
V = n/C
= 2.5 mol/15.0 mol/L
= 0.167 L
= 167 mL of 15.0 M H₂SO₄ reacts with 45.0 g Al to produce aluminum sulfate.
b. From the chemical reaction, 2 mol Al produces 1 mol Al₂(SO₄)₃
Therefore 1.668 mol Al will produce x mol Al₂(SO₄)₃. So, x = 1 mol × 1.668 mol/2 mol = 0.834 mol
So, we need to find the mass of 0.834 mol Al₂(SO₄)₃. Now molar mass Al₂(SO₄)₃ = 2 × 26.98 g/mol + 3 × 32 g/mol + 4 × 3 × 16 g/mol = 53.96 g/mol + 96 g/mol + 192 g/mol = 341.96 g/mol.
Also number of moles of Al₂(SO₄)₃, n = mass of Al₂(SO₄)₃,m/molar mass Al₂(SO₄)₃, M
n =m/M
So, m = nM = 0.834 mol × 341.96 g/mol = 285.2 g
% yield = Actual yield/theoretical yield × 100 %
Actual yield = 112 g, /theoretical yield = 285.2 g
So, % yield = 112 g/285.2 g × 100 %
= 0.3927 × 100 %
= 39.27 %
The volume (mL) of 15.0 M sulfuric acid needed to react with 45.0 g of aluminum is 166mL and % yield of the reaction is 39.46%.
How do we calculate moles?Moles of any substance will be calculated by using the below formula as:
n = W/M, where
W = given mass
M = molar mass
Given chemical reaction is :
2Al(s) + 3H₂SO₄(aq) → Al₂(SO₄)₃(aq) + 3H₂(g)
Moles of 45g of Al will be calculated as:
n = 45g / 27g/mol = 1.66 mole
From the stoichiometry of the reaction, it is clear that:
1.66 moles of Al = react with 3/2×1.66=2.49 moles of H₂SO₄
By using the formula of molarity we can calculate the volume of H₂SO₄ as:
M = n/V
V = (2.49) / (15) = 0.166L = 166mL
Again from the stoichiometry it is clear that:
1.66 moles of Al = produces 1/2×1.66= 0.83 moles of Al₂(SO₄)₃
Mass of 0.83 moles of Al₂(SO₄)₃ = (0.83mol)(341.96g/mol) = 283.82 g
Given actual yield of Al₂(SO₄)₃ = 112g
% yield will be calculated as:
Percent yield = (Actual yield/Theoretical yield) × 100
% yield = (112/283.82) × 100 = 39.46%
Hence required values are discussed above.
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If 75J of heat are applied to 8.4 L of a gas at 732 mmHg and 298K, what is the final temperature, in K, of the gas? Cp for an ideal gas is 20.79 J/mol*K.
Answer:
309 K
Explanation:
Step 1: Convert the pressure to atm
We will use the conversion factor 1 atm = 760 mmHg.
732 mmHg × 1 atm/760 mmHg = 0.963 atm
Step 2: Calculate the moles (n) of the ideal gas
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 0.963 atm × 8.4 L/0.0821 atm.L/mol.K × 298 K
n = 0.33 mol
Step 3: Calculate the temperature change
We will use the following expression.
Q = n × Cp × ΔT
ΔT = Q/n × Cp
ΔT = 75 J/0.33 mol × 20.79 J/mol.K
ΔT = 11 K
Step 4: Calculate the final temperature
T = 298 K + 11 K = 309 K
Which one elutes first 3-methylcyclohexene or
1-methylcyclohexene in gas chromatography and why? (In terms of stationary phase / boiling point / retention time)
Answer:
3-methylcyclohexene
Explanation:
In gas chromatography, the compound with the lower boiling point will have shorter time in the gas phase, resulting in fewer theoretical plates and a decreased retention time. Once a product exits the column it is transferred to the graph after passing through a detector which picks up on the differing conductance of the carrier gas vs. the carrier gas and product
There are two types of gas chromatography, they are gas liquid chromatography and gas solid chromatography. Here 3 - methyl cyclohexene will elutes first as compared to 1-methylcyclohexene.
What is gas chromatography?In gas liquid chromatography, the mobile phase is a gas and the stationary phase is a liquid immobilized on the surface of an inert solid support. The technique is based on the differential partitioning of the components of a sample in the vapor phase between the mobile gas phase and the stationary liquid phase.
In gas chromatography, the component with a lowest boiling point is found to has a shorter time in the gas phase and it will elute first as compared to the component with highest boiling point.
Here 3-methylcyclohexene is more substituted than 1-methylcyclohexene. The boiling point of 3-methylcyclohexene is less as compared to that of 1-methylcyclohexene. So 3-methylcyclohexene elute first.
Thus 3-methylcyclohexene elute first.
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Ammonia gas(NH3) and oxygen(O2) gas react to form nitrogen gas and water vapor. Suppose you have 2.0 mol of and 13.0 mol of O2 in a reactor. Calculate the largest amount of that could be produced. Round your answer to the nearest .
Answer:
[tex]n_{H_2O}=3.0molH_2O\\\\n_{N_2}=1.0molN_2[/tex]
Explanation:
Hello!
In this case, for the described reaction we have:
[tex]2NH_3(g)+\frac{3}{2} O_2(g)\rightarrow N_2(g)+3H_2O(g)[/tex]
Which means there is 2:3/2 mole ratio between ammonia and oxygen and we use it to compute the consumed moles of ammonia by 13.0 moles of oxygen as shown below:
[tex]n_{NH_3}^{consumed \ by\ O_2}=13.0molO_2*\frac{2molNH_3}{\frac{3}{2}molO_2 } =17.33molNH_3[/tex]
However, since just 2.0 mol of ammonia is available, we infer it is the limiting reactant and the maximum amount of both nitrogen and water that can be produced is computed below:
[tex]n_{H_2O}=2.0molNH_3*\frac{3molH_2O}{2molNH_3} =3.0molH_2O\\\\n_{N_2}=2.0molNH_3*\frac{1molN_2}{2molNH_3} =1.0molN_2[/tex]
Best regards!
Which of the following belong to a category called the main group of elements
A halogens
B nonmetals
C alkaline metal
D transition elements
Answer:
C. Alkaline Metal ok thanks
What name is given to the elements that appear in the right-most column of the periodic
table?
- Alkali metals
- Alkaline earth metals
- Transition metals
- Noble gases
(NOBLE GASES IS ANSWERR)
Answer:
Noble gases... (You already know...)
Explanation:
The right-most column of the periodic table contains atoms with full electron shells, also known as Noble Gases.
Hope this helped!
Answer:
Noble gases
Explanation:
The six elements listed in the last column of the table (Group 18) of the periodic table are collectively referred to as the noble gases. All of the noble gases have the maximum number of electrons possible in their outer shells (two electrons in helium’s outer shell, and eight electrons for all the others), making them stable.
an electric current causes water to be transformed into hydrogen and oxygen gasses a physical change or a chemical change
A photon of blue light has a wavelength of 4.62 x 10m (462 nm). Calculate the energy of this photon
Answer:
[tex]E=4.3\times 10^{-19}\ J[/tex]
Explanation:
Given that,
The wavelength of a photon of blue light is 462 nm
We need to find the energy of this photon. The formula for the energy of a photon is given by :
[tex]E=\dfrac{hc}{\lambda}\\\\E=\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{462\times 10^{-9}}\\\\=4.3\times 10^{-19}\ J[/tex]
So, the energy of this photon is [tex]4.3\times 10^{-19}\ J[/tex].
Given this reaction: 4K(s) + O2(g)→2K2O(s). Calculate how many grams of product is produced if 2.50 g of each reactant is reacted.
PLEASE HURRY!!!
Answer:
[tex]m_{K_2O}^{by\ K} =3.01gK_2O[/tex]
Explanation:
Hello!
In this case, since 2.50 g of both potassium (molar mass = 39.1 g/mol) and gaseous oxygen (molar mass = 32.0 g/mol) react in a 4:1 and 1:2 mole ratio respectively, to produce potassium oxide (molar mass = 94.2 g/mol), we evaluate the mass of potassium oxide yielded by each reactant in order to identify the limiting one via stoichiometry:
[tex]m_{K_2O}^{by\ K}=2.50gK*\frac{1molK}{39.1gK}*\frac{2molK_2O}{4molK}*\frac{94.2gK_2O}{1molK_2O} =3.01gK_2O\\\\m_{K_2O}^{by\ O_2}=2.50gO_2*\frac{1molO_2}{32.0gO_2}*\frac{2molK_2O}{1molO_2}*\frac{94.2gK_2O}{1molK_2O} =14.7gK_2O[/tex]
Thus, since the 2.50 g of potassium yields 3.01 g of potassium oxide, we infer it is the limiting reactant and that is the mass of produced product by the reaction.
Best regards!
Answer: Calculating mass quick check
1. The mass of the reactants must be equal to the mass of the products. The total number of moles of the reactants can be more or less than the total number of moles of the products.
2. Divide the mass of the reactant by its molar mass to find the number of moles of the reactant. Use the chemical equation to find the number of moles of the product. Multiply the number of moles of the product by its molar mass to find the mass of the product.
3. 2(108 g/mol)+32 g/mol=248 g/mol; (248 g/mol)(0.02 mol)=4.96 g
4. 19.5 g
5. 853.5 g
You're welcome
a sample gas is in the rigid cylinder with a movable piston the pressure of the gas is kept constant if the kelvin temperature of the gas is doubled the volume of the gas is?
Answer:
The pressure of the gas is kept constant. If the Kelvin temperature of the gas is doubled, the volume of the gas is. O 1.
Give an
example of when a plant or animal might
use energy they have stored.
Answer:
hunting for other animals or when they are really hungry
Explanation:
We have that for the Question "Give an example of when a plant or animal might use energy they have stored. " it can be said that
Plants may use the energy in food synthesizing and the may also use the stored energy in excretion. Animals store the energy for use during hibernation
From the question we are told
Give an example of when a plant or animal might use energy they have stored.
Generally
Plants tend to hold energy as starch and break them down to glucose to usePlants may use the energy in food synthesizing and the may also use the stored energy in excretion.
While most animals store the energy for use during hibernation .a season when they go without food or water and no movement due to the season
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Find the pH and fraction of association of a 0.100 M solution of the weak base B with Kb = 1.00 x 10^5.
Answer:
Fraction of association = 0.01
pH = 11
Explanation:
A weak base, B, is in equilibrium with water as follows:
B(aq) + H2O(l) ⇄ BH⁺(aq) + OH⁻(aq)
Where Kb is defined as:
Kb = 1.00x10⁻⁵ = [BH⁺] [OH⁻] / [B]
Some B will react producing BH⁺ and OH⁻:
[BH⁺] = X
[OH⁻] = X
[B] = 0.100M - X
As Kb <<< [B] we can say:
[B] ≈ 0.100M
Replacing:
1.00x10⁻⁵ = [X] [X] / [0.100]
1.00x10⁻⁶ = X²
X = 1x10⁻³M = [BH⁺] = [OH⁻]
The fraction of association is [BH⁺] / [B] = 1x10⁻³M / 0.100M = 0.01
As [OH⁻] = 1x10⁻³M, pOH = -log[OH⁻] = 3
pH = 14- pOH
pH = 11Can anyone help pretty please