The reason for adding a limited amount and then an excess amount is that initially a metal hydroxide may form which becomes soluble when more base is added and the metal complex forms.
In qualitative analysis is a common to add the base in drops and then in excess. When added in drops, the metal hydroxide is formed. This metal hydroxide is often insoluble.
After this metal hydroxide is formed, the base could be added in excess such that the metal hydroxide dissolves in the excess base by forming a complex.
For instance;
CuCl2(aq) + 2NaOH(aq) -------> Cu(OH)2(s) + 2NaCl(aq)
Cu(OH)2(s) + 2OH^-(aq) -------> [Cu(OH)4]^2+(aq)
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The water in a fishery became polluted when toxic waste was dumped into its pond, causing the fish population to substantially decline. The percents of fish that survived are recorded in the table.
Day 1 2 3 4 5
% Survival 79 55 38 31 19
a) What is the order of the reaction live fish ------> dead fish?
b) What is the rate constant?
c) If the fish continue to die at this rate, how many fish will be alive after 10 days?
In the pond, the percentage of fish left after ten days is 4%.
Given that;
N(t) = Noe^-kt
Where;
N(t) = percentage of fish at time t
No = Initial percentage of fish
k = rate constant
t = time taken
Given that we had 100% fish population at the beginning, we can see that this reaction is first order.
The rate constant is obtained from;
When t = 5
19 = 100e^-5k
19/100 =e^-5k
0.19 = e^-5k
ln 0.19 = -5k
k = ln (0.19)/-5
k = 0.33
In ten days;
N(10) = 100e^-0.33(10)
N(10) = 4%
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THIS IS MY LAST WUESTION FOR MY TEST I ONLY HAVE 30 MINS LEFT TO ASNWER HELP.
Tiffany decided to make a salad for her lunch. She combined Lettuce, croutons, bacon,
cucumbers, cheese, ham and salad dressing into her bowl. As she was adding each different
ingredient, she tasted each one to make sure that she like it. When she was done, she ate her
salad. She noticed while she was eating the salad, that it had a different flavor than each of the
original ingredients. What type of change occurred?
Homogenous change
A solution change
A chemical change
A physical change
calculate the mass in grams of two cubic inches (2.00 in³)" of gold. density of gold =19.3 g cm-.³
Taking into account the definition of density, the mass of two cubic inches (2.00 in³) of gold is 632.54 grams.
But first you must know the definition of density. Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.
In other words, density is a scalar quantity referring to the amount of mass in a given volume of a substance, that is, it shows the relationship between the weight (mass) of a substance and the volume it occupies.
Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:
[tex]density=\frac{mass}{volume}[/tex]
In this case, you know that:
Density= 19.3 g/cm³ Volume= 2 in³= 32.7741 cm³ (being 1 in³= 16.3871 cm³)Replacing in the definition of density:
[tex]19.3\frac{g}{cm^{3} } =\frac{mass}{32.7741 cm^{3} }[/tex]
Solving:
mass= 19.3 [tex]\frac{g}{cm^{3} }[/tex]× 32.7741 cm³
mass= 632.54 g
In summary, the mass of two cubic inches (2.00 in³) of gold is 632.54 grams.
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Where is groundwater stored?
Answer:
Answer Below! : )
Explanation:
Groundwater is stored in the tiny open spaces between rock and sand, soil, and gravel. How well loosely arranged rock (such as sand and gravel) holds water depends on the size of the rock particles.
Hope this helps! : )
Answer:
Underground brainliest plz
Explanation:
Aluminium sulphate is organic or inorganic compound
Answer:
Aluminium sulphate is an inorganic compound.
A solution is prepared by diluting 6.0 mL of a 7.6 x 10-4 g/mL solution to a total volume
of 10.0 mL. Calculate the concentration of the dilute solution.
Answer:
4.56 X 10^ -4 g/mL
Explanation:
A solution is prepared by diluting 6.0 mL of a 7.6 x 10-4 g/mL solution to a total volume of 10.0 mL. Calculate the concentration of the dilute solution.
(7.6 X10^-4 gm/m L) x( 6.0 m L ) = 45.6 X 10^-4 g
this is dissolved )in 10 m L=45.6 X 10^-4 g/ 10
4.56 X 10^ -4 g/mL
check
6/10 =0.6
4.56/7.6 = o.,6
b. How does government funding affect scientific progress? (1 point)
Answer:
29 percent of federal R&D money goes to universities, 29 percent goes to industry, and another 29 percent goes to researchers who work directly for federal agencies. About 10 percent goes to federally funded labs operated by private contractors.
Answer:
Explanation:
Funding from the government greatly affects the scientific research as a research can take number of years to complete. During this time period lot of financial support is required as there might be lot of expensive chemicals or substance that the scientist requires for his research.
Write the full electron configuration for a Ca+ ion.
Answer:
[Ar] 4s²
Explanation:
The full electron configuration for the Ca+ ion is:
1s² 2s² 2p⁶ 3s² 3p⁶.
How to determine the electron configuration for the Ca+ ionTo determine the full electron configuration for a Ca+ ion, we need to remove one electron from the neutral calcium atom (Ca). The neutral calcium atom has the electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
When Ca loses one electron to form the Ca+ ion, the electron removed comes from the highest energy level, which is the 4s orbital.
Therefore, the full electron configuration for the Ca+ ion is:
1s² 2s² 2p⁶ 3s² 3p⁶.
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Hi. Please tell me When you test starch with Barfoed’s reagent, what would be the answer, positive or negative? Explain the answer by giving reasons and structures.
[EASY][50pt] Temperature vs Time Graph
5. In what state of matter does this substance exist at the 22 minute mark?
6.At what temperature does condensation occur?
7.What phase change occurs at 70C
#5
At 22min the temperature is at 40°C
So the matter is at solid state.#6
Graph ended at 20°C so condetion occured at 20°C
#7
After 70°C the matter got melted do its at liquid state
How many mL of 1.76 M sodium hydroxide solution (strong base) must be added to 0.75
Macetic acid to make 683 mLa pH 49 buffer? (pka of acetic acid is 4.76)
Answer: Special care is required to prepare a solution of sodium hydroxide or NaOH in water because considerable heat is liberated by the exothermic reaction. The solution may splatter or boil. Here is how to make a sodium hydroxide solution safely, along with recipes for several common concentrations of NaOH solution.
Explanation:
Hope this helps!
The ancient Egyptians planted crops and raised
animals for food as early as?
100 AD.
2000 BCE.
5200 BCE.
2560 BCE.
How many protons, neutrons, and electrons are there in a neutral atom of 60 Co (cobalt- 60 )?
Cobalt-60 is comprised of 27 protons, 33 neutrons, and 27 electrons. Nuclear reactors are used to artificially create it.
What is cobalt- 60?A radioactive isotope containing cobalt with something like a half-life of 5.2713 centuries is called cobalt-60 (60Co). Nuclear reactors are used to artificially create it. Neutron irradiation of bulk material of the monoisotopic as well as mononuclidic cobalt element 59 Co is necessary for deliberate industrial manufacture.
The accidentally generated 60 Co in the latter instance (inside the absence of additional cobalt) is mostly the product of many phases involving neutron activation on iron isotopes inside the reactor. Cobalt-60 is comprised of 27 protons, 33 neutrons, and 27 electrons.
Therefore, cobalt-60 is comprised of 27 protons, 33 neutrons, and 27 electrons.
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Calculate the moles of calcium oxalate formed from 5 grams of potassium oxalate (molar mass 184.24 g/mol) the mole mole ratio from the balanced equation is 2.1 potassium oxalate to calcium oxalate
5 g of potassium oxalate react to produce 0.03 moles of calcium oxalate.
Calcium oxalate (CaC₂O₄) is obtained by the reaction of 5 g of potassium oxalate (K₂C₂O₄).
We can calculate the moles of CaC₂O₄ obtained considering the following relationships.
The molar mass of K₂C₂O₄ is 184.24 g/mol.The mole ratio of K₂C₂O₄ to CaC₂O₄ is 2:1.[tex]5 g K_2C_2O_4 \times \frac{1molK_2C_2O_4}{184.24gK_2C_2O_4} \times \frac{1molCaC_2O_4}{2molK_2C_2O_4} = 0.03molCaC_2O_4[/tex]
5 g of potassium oxalate react to produce 0.03 moles of calcium oxalate.
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Please for real help me, show work !
Answer:
27)
a. Silver nitrate
b. Lead chromate
c. Anhydrous magnesium acetate
d. Copper nitrate
28) a. KNo3
Complete the table below by deciding whether a precipitate forms when aqueous solutions A and B are mixed. If a precipitate will form, enter its empirical
formula in the last column.
solution A
solution B
Does a
precipitate form
when A and B
are mixed?
Oyes no
empirical
formula of
precipitate
х
X
x
5
?
copper(II) chloride
sodium sulfide
potassium sulfate
O yes no
lead(II) nitrate
ammonium bromide
sodium hydroxide
O yes no
Que
The reaction between copper II chloride and sodium sulfide as well as lead II nitrate and potassium sulfate both produce precipitates.
The solubility of a substance in water is in accordance with the solubility rules. It is possible that a solid product may be formed when two aqueous solutions are mixed together. That solid product is referred to as a precipitate.
Now, we will consider each reaction individually to decode whether or not a precipitate is possible.
In the first reaction, we have; CuCl2(aq) + Na2S(aq) ---->CuS(s) + 2NaCl(aq). A precipitate (CuS) is formed.In the second reaction, Pb(NO3)2(aq) + 2KNO3(aq) ----> PbSO4(s) + KNO3(aq), a precipitate PbSO4 is formedIn the third reaction, NH4Br(aq) + NaOH(aq) ----->NH3(g) + NaBr(aq) + H2O(l), a precipitate is not formed here.Learn more: https://brainly.com/question/11969651
highlight main approaches that could be used to investigate the waterer Quality.
Answer:
Seven methods were used to assess water quality in the river system. These methods included single-factor assessment, water quality grading, comprehensive pollution index, the Nemerow pollution index, principle component analysis, fuzzy comprehensive evaluation, and comprehensive water quality identification index.
15.3 Determine the mass of the following: 15.3.1. 2 mol calcium atoms
15.3.2. 0,3 mol nitrogen molecules
15.3.3. 0,5 mol table salt
15.3.4. 0,2 mol hydrochloric acid
15.3.5. 0,08 mol sodium carbonate (Na2CO3)
15.3.6. 0,25 mol ammonium sulphate (NH4)2SO4
Answer:
htyiu
Explanation:
state why vulcanologist make predications about when a volcano will erupt
Answer:
They want to know how long it has been since it last erupted.
Explanation:
Scientists study a volcano's history to try to predict when it will next erupt. They also want to know the time span between its previous eruptions
How many milligrams are in 2.89 x 1024 CO2 molecules?
Answer:
2,959.36
Explanation:
There are 2959.36 milligrams present in 2.89 x [tex]10^{24}[/tex] CO2 molecules.
What is molecule?The smallest component of a substance which possesses both its chemical as well as physical characteristics. One or even more atoms make up molecules.
What is milligrams?Such a measure of mass as well as weight that weighs 0.0154 grains or one-thousandth of a gram.
Calculation of milligram in CO2 molecule.
Mass = No. of molecule / molar mass.
Molar mass = 44.02 g/mol.
Mass = 2.89 x [tex]10^{24}[/tex] /[tex]6.023 * 10^{23}[/tex]× 44.02 g/mol.
Mass = 2959.36 milligrams
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When a sample of iron ore of mass 2.016 g is treated with 50.0 mL of hydrochloric acid, the iron dissolves in the acid to form a solution of . The solution is diluted to 100.0 mL and the concentration of ions is determined by spectrometry to be . What is the mass percentage of iron in the ore
Phản ứng phân hủy dinitơ pentaoxide N2O5 là một phản ứng bậc 1 có giá trị hằng số tốc độ
K = 5,1.10-4
s
-1
tại 45oC.
2N2O5(k) → 4NO2(k) + O2(k)
a. Biết nồng độ ban đầu của N2O5 là 0,25M, hỏi sau 3,2 phút nồng độ của nó là bao nhiêu?
b. Sau bao lâu nồng độ N2O5 giảm từ 0,25M thành 0,15M?
c. Sau bao lâu chuyển hóa hết 62% N2O5?
Which has more calories: table sugar or aspartame?
Answer:
Aspartame produces 4 kilocalories of energy per gram when metabolized, sucrose (table sugar) produces 3.9 kilocalories. However, aspartame is approximately 200 times sweeter than sucrose, so it is consumed in much smaller doses.
Explanation:
Answer is Aspartame.
Select the correct answer.
What are the products in the following chemical reaction?
Pb(NO3)2 + KCl
What physical and chemical properties would an antique dealer use to determine the substance that makes up a
piece of jewelry?
Answer:
Characteristics such as melting point, boiling point, density, solubility, color, odor, etc. are physical properties. Properties that describe how a substance changes identity to produce a new substance are chemical properties. ... Physical and chemical properties can be used to classify a substance as ionic or molecular.
Please answer question (e)
Answer:
here is no question (e).............
Determine the molar solubility for Cr(OH)3 Ksp = 6.3x10^-31 ....
a) Set up the ICE table Cr(OH)3 (s) <-> Cr^3+ (aq) + 3OH^- (aq)
b) Ksp expression
c) Determine molar solubility
The equilibrium constant shows the extent of dissolution of a substance in solution. The molar solubility of the compound here is 1.2 * 10^-8 M.
What is solubility product?The solubility product is the equilibrium constant that shows the extent to which a substnace is dissolved in soution.
Now let us set up the ICE table as shown;
Cr(OH)3 (s) <-> Cr^3+ (aq) + 3OH^- (aq)
I 0 0
C +x +3x
E x 3x
Ksp = [Cr^3+] [OH^- ]^3
6.3x10^-31 = [x] [3x]^3
6.3x10^-31 = 27x^4
x = 4√6.3x10^-31 /27
x = 1.2 * 10^-8 M
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Radar images storms by
22. What is the mass in grams of each of the following?
a. 3.011 x 1023 atoms F
b. 1.50 x 1023 atoms Mg
c. 4.50 x 1012 atoms Cl
d. 8.42 x 1018 atoms Br
e. 25 atoms W
f. 1 atom Au
The mass in grams of 3.011 x 10²³ atoms of F is 9.5 g.
The mass in grams of 1.50 x 10²³ atoms of Mg is 5.98 g.
The mass in grams of 4.50 x 10¹² atoms of Cl is 2.65 x 10⁻¹⁰ g.
The mass in grams of 8.42 x 10¹⁸ atoms of Br is 1.12 x 10⁻³ g.
The mass in grams of 25 atoms of W is 3.1 x 10⁻²¹ g.
The mass in grams of 1 atom of Au is 3.27 x 10⁻²² g.
What is the mass in grams of 3.011 x 10²³ atoms F?
The mass in grams of 3.011 x 10²³ atoms of F is calculated as follows;
6.023 x 10²³ atoms = 19 g of F
3.011 x 10²³ atoms F = ?
= (3.011 x 10²³ x 19 g)/(6.023 x 10²³)
= 9.5 g
The mass in grams of 1.50 x 10²³ atoms of Mg is calculated as follows;
6.023 x 10²³ atoms = 24g of Mg
1.5 x 10²³ atoms F = ?
= (1.5 x 10²³ x 24 g)/(6.023 x 10²³)
= 5.98 g
The mass in grams of 4.50 x 10¹² atoms of Cl is calculated as follows;
6.023 x 10²³ atoms = 35.5 g of Cl
4.5 x 10²³ atoms Cl = ?
= (4.5 x 10¹² x 35.5 g)/(6.023 x 10²³)
= 2.65 x 10⁻¹⁰ g
The mass in grams of 8.42 x 10¹⁸ atoms of Br is calculated as follows;
6.023 x 10²³ atoms = 80 g of Br
8.42 x 10¹⁸ atoms Br = ?
= (8.42 x 10¹⁸ x 80 g)/(6.023 x 10²³)
= 1.12 x 10⁻³ g
The mass in grams of 25 atoms of W is calculated as follows;
6.023 x 10²³ atoms = 74 g of W
25 atoms W = ?
= (25 x 74 g)/(6.023 x 10²³)
= 3.1 x 10⁻²¹ g
The mass in grams of 1 atom of Au is calculated as follows;
6.023 x 10²³ atoms = 197 g of Au
1 atom of Au = ?
= (1 x 197 g)/(6.023 x 10²³)
= 3.27 x 10⁻²² g
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Which layer is thin, brittle, solid, and composed primarily of silica?
the crust
the mantle
the outer core
the inner core