Answer:
K₂Cr₂O₇
Explanation:
Finding % of O
% O = 100% - % K - % Cr% O = 100% - 26.56% - 34.51%% O = 73.44% - 34.51%% O = 38.93%Steps
Change % of each element into grams.Convert grams of each element into moles by dividing grams by molar mass.Divide all moles by the smallest number of moles.If the moles are all whole numbers, then you’re done and that’s your empirical formula.If not, multiply all moles by number such that everything is a whole number.Solving
We have 26.56g of K, 34.51g of Cr, and 39.93g of O
Moles of K, n(K) = 26.56/39.0983 = 0.68 molesMoles of Cr, n(Cr) = 34.51/51.9961 = 0.66 molesMoles of O, n(O) = 38.93/15.9994 = 2.43 molesK = 0.68/0.66 ≈ 1 x 2 = 2Cr = 0.66/0.66 = 1 x 2 = 2O = 2.43/0.66 = 3.5 x 2 = 7The empirical formula is K₂Cr₂O₇
Help! 100 point and I will give a brainliest and 5 star for solving this question.
100ml of 0.1 N H2SO4 by diluting from original H2SO4.
Atomic mass of: O=16 , H=1 S=32
d H2SO4=1.08 purity%=98%
i need the solution.
Mass of H_2SO_4 required
Molarity
Moles of solute/Volume of solution in LSo
0.1=n/0.1Ln=0.1(0.1)n=0.01molNow molar mass of H_2SO_4
2(1)+32+4(16)2+32+6498g/molMass
98(0.01)0.98g
What is the molarity of a solution that has 450 grams of sodium chloride in 800.0 mL of
water?
Answer:
= 9.6125M
Explanation:
data:
volume = 800ml
800/ 1000 = 0.8dm^3
molar mass of NaCl = 23 + 35.5
= 58.5g
mass of NaCl = 450 g
moles= ?
molarity = ?
solution:
no. of moles = [tex]\frac{given mass}{molar mass}[/tex]
= 450 / 58.5
= 7.69 moles
now, molarity = [tex]\frac{moles}{volume in dm^3}[/tex]
= 7.69 / 0.8
molarity= 9.6125 M
Which is NOT included
in the appendicular
skeleton?
B. leg bones
A. arm bones
D. pelvic bones
C. ribs
Answer:
C. ribs.
Explanation:
The appendicular skeleton includes the shoulder girdles and arm bones, the pelvic gridle and the lower limb bones (leg bones). The ribs is part of the axial skeleton.
For each reaction below, use the drop-down menus to select which compound will form a precipitate. Note: It is possible that no precipitates form. Na2S + Cd(NO3)2 → CdS + 2NaNO3 FeCl3 + 3KOH → 3KCl + Fe(OH)3 Na2CO3 + Ba(NO3)2 → BaCO3 + 2NaNO3
Answer:
1. Cadmium sulfide
2. Iron (III) hrydroxide
3. Barium carbonate
Cadmium sulfide, iron hydroxide, and barium carbonate will form a precipitate.
What is Precipitation Reaction?The precipitation reaction can be described as a chemical reaction taking place in an aqueous solution where two ionic bonds combine in order to form an insoluble salt.
These insoluble salts form are called precipitates in precipitation reactions. Precipitation reactions are commonly double displacement reactions in which the production of a solid forms a residue known as the precipitate.
The first reaction: [tex]Na_2S + Cd(NO_3)_2 \longrightarrow CdS + 2NaNO_3[/tex]
The cadmium sulfide forms precipitates in this reaction.
The second reaction: [tex]FeCl_3 + 3KOH \longrightarrow 3KCl + Fe(OH)_3[/tex]
The iron hydroxide forms precipitate in this reaction.
The third reaction:[tex]Na_2CO_3 + Ba(NO_3)_2 \longrightarrow BaCO_3 + 2NaNO_3[/tex]
The barium carbonate forms precipitate in this reaction.
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How much heat does it take to warm 16.0 g of pure water from 90.0 degree C to 100.0 degree C?
The specific heat of water = 4.18 J/g. degree C
16.0 Joules
160 Joules
66.9 Joules
669 Joule
[tex]{\huge{\fcolorbox{yellow}{red}{\orange{\boxed{\boxed{\boxed{\boxed{\underbrace{\overbrace{\mathfrak{\pink{\fcolorbox{green}{blue}{Answer}}}}}}}}}}}}}[/tex]
669 J
Right option is D.
Step by Step Explanation:
[tex] \sf Mass \: of \: water(m) = 16g \\ \\ \sf Specific \: heat \: of water(C) = 4.18J/g \\ \\ \sf Change \: in \: temperature ( \triangle T) = 100 - 90 = 10{ \degree}C[/tex]
[tex] \sf \large \red{ Heat = mC\triangle T}[/tex]Now substituting the required values.
[tex] \sf \hookrightarrow Heat = 16 \times 4.18 \times 10 \\ \\ \sf \hookrightarrow Heat = 668.8(approx) \\ \\ \blue {\boxed { \hookrightarrow{Heat = 669J }}}[/tex]
What is the percent composition of Cesium and Fluorine in CsF?
The percent composition of Cesium and Fluorine in CsF are 87.493 % and 12.507 % respectively.
What is a percentage composition?Percent composition is very simple. Percent composition tells you by mass what percent of each element is present in a compound.
Molecular mass of Cs = 132.9054519
Molecular mass of F = 18.9984032
Molecular mass of CsF = 132.9054519 + 18.9984032 = 151.9038551
CsF: Percent composition by element:
Cesium (Cs) = [tex]\frac{32.9054519 X 100}{151.9038551}[/tex] = 87.493 %
Fluorine (F) = [tex]\frac{18.9984032 X 100 }{151.9038551}[/tex]= 12.507 %
Hence, the percent composition of Cesium and Fluorine in CsF are 87.493 % and 12.507 % respectively.
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contribution of chemistry in medicines
Answer:
Chemistry in Medicine
Explanation:
Major contributions to health care have been made by chemistry. The development of new drugs involves chemical analysis and synthesis of new compounds. Many recent television programs advertise the large number of new
drugs produced by chemists.
BRAINLIEST MEEEE PLSS
it is said that what in the universe is made of either matter or energy
Answer:
normal matter, dark matter , dark energy
How many moles of nitrogen atoms are there in 1.64 x 1023 molecules of dinitrogen trichloride, N2Cl3?
The number of moles of nitrogen atoms are there in 1.64 x 1023 molecules of dinitrogen trichloride is 0.544.
What are a number of moles?The mole is a SI unit of measurement that is used to calculate the quantity of any substance.
1 mole is 6.022 × 10²³
[tex]1\; molecule = \dfrac{1}{6.023 \times 10^2^3}[/tex]
The given number of moles are 1.64 x 10²³
[tex]1.64 \times 10^2^3= \dfrac{1}{6.023 \times 10^2^3} = 0.272 \\[/tex]
Now, there are two molecules of nitrogen in the dinitrogen trichloride
So, 0.272 x 2 = 0.544
Thus, the number of moles of nitrogen atoms are there in 1.64 x 1023 molecules of dinitrogen trichloride is 0.544.
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1. How many moles are in 78.9g of HCI?
where would you find water on the ph scale?
Answer: between 6.5 and 8.5
Explanation:
As shown in my science book it appears in the ph scale
HPO42- is an amphoteric ion. Is the Ka or Kb for this ion larger? (Hint: Consider
what its conjugate acid and conjugate base are in calculating the constants.)
Would you expect it to behave more like an acid or a base?
Sibce its Kb is larger than its Ka, the monohydrogen phosphate ion, HPO4^2- will behave more as a base than as an acid.
What is an amphoteric ion?An amphoteric ion is an ion that can act both as an acid or a base.
An example of an amphoteric ion is monohydrogen phosphate ion,
[tex]HPO_4^{2-}[/tex]
The Ka of monohydrogen phosphate ion is 4.8 × 10^-13 while the Kb is 1.6 × 10^-7.
The In is greater than the Ka.
Therefore, the monohydrogen phosphate ion, HPO4^2- will behave more as a base than an acid.
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Question 29 of 30
The thermochemical equation for the reaction of pentane and oxygen is
shown below. What does the equation tell you about the reaction?
C,H,(g)+80,(g) → 500,(g) + 6H2O(g) + 3536 kJ
O A. It is endothermic.
B. It has a low activation energy.
C. It has a high activation energy.
D. It is exothermic.
does vitamin b1 contain chemicals or a chemical reaction
Name the following carboxylic acid:
COOH
A. 3-ethyl-2-methylheptanoic acid
B. 2-ethyl-1-methylhexanoic acid
The name of the compound is 2-methyl-3-ethylheptanoic acid.
Naming organic compoundsLooking at the structure, the longest carbon chain is 7. Meaning that the compound is a heptanoic acid.
There are 2 branches. The first one has a single carbon (methyl) while the second one has 2 carbons (ethyl).
The methyl is located on the second carbon (2-methyl) while the ethyl is located on the third carbon (3-ethyl) on the main chain.
Thus, the name of the compound would be 2-methyl-3-ethylheptanoic acid.
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Answer:its c 3-ehtyl
Explanation:
essay of poverty 500 words
Poverty is defined as a situation in which a family's fundamental necessities, such as food, housing, clothes, and education, are not met. It can lead to additional issues such as low literacy, unemployment, and starvation, among others. Due to a lack of funds, a poor individual is unable to obtain an education and hence remains unemployed. Unemployed people are unable to provide sufficient and healthy food for their families, and their health suffers as a result. A person who is weak lacks the necessary energy for the work. A unemployed individual would always be impoverished. As a result, we might claim that poverty is the basis of all other issues.
The United Nations has created two methods for evaluating poverty: absolute and relative poverty. In developing nations like India, absolute poverty is used to assess poverty. In industrialized countries like the United States, relative poverty is employed to quantify poverty. A poverty line has been established based on the minimum level of income in absolute poverty. If a family's daily income is less than this, they are poor or living in poverty. If a family's daily income exceeds this amount, it is considered non-poor or above the poverty line. The new poverty threshold in India is Rs 32 in rural areas and Rs 47 in cities.
"Poverty is not natural; it is manufactured," said Nobel Laureate and South African leader Nelson Mandela. The preceding remark is correct since most causes of poverty are caused by humans. Poverty has several causes, but the most significant is population growth. Countries' resources and budgets are being strained by rising population. Food, housing, and work are becoming increasingly difficult for governments to supply.
Lack of education, conflict, natural disasters, a lack of job, a lack of infrastructure, political instability, and so on are some of the other factors. For example, a person becomes jobless due to a lack of employment prospects and is unable to earn enough to meet his family's basic needs, resulting in poverty. Lack of knowledge forces a person to accept lower-paying occupations, making him poorer. Lack of infrastructure indicates that a country lacks industry, banks, and other institutions, resulting in a labor shortage. Natural calamities such as floods and earthquakes exacerbate poverty.
A protracted period of civil conflict in certain nations, particularly African ones like Somalia, has resulted in widespread poverty. This is because all of the resources and money are being diverted to the war effort rather than public welfare. Natural catastrophes, such as cyclones, are common in countries like India, Pakistan, and Bangladesh. Every year, these calamities occur, leading poverty to grow.
A poor family's life is affected by poverty. Poor people are unable to consume adequate food and nourishment, and their capacity to work is reduced. His income is further reduced by his reduced capacity to work, leaving him impoverished. Children from low-income families do not receive adequate education or nourishment. They must work in order to support their families, which ruins their childhood. Some of them may be involved in crimes such as theft, murder, and robbery, among others. A poor individual is illiterate and forced to live in slums in unsanitary conditions. In slums, there is no basic sanitation or drinking water, therefore he gets sick frequently and his health deteriorates. A disadvantaged individual is more likely to die young. As a result, all societal ills are linked to poverty.
The Indian government has also taken many steps to reduce poverty in the country. Some of these include establishing job opportunities, population control, and so on. In India, almost 60% of the population still relies on agriculture for a living. The Indian government has taken steps to boost agriculture. In our nation, the government built dams and canals to offer convenient access to water for irrigation. To support agriculture, the government has also made initiatives to make seeds and farming equipment more affordable. The government is also encouraging the cultivation of commercial crops such as cotton rather than food crops. The government is supporting manufacturing in cities in order to create more jobs. 'Ration stores' have also been established by the government.
Other initiatives include free and obligatory education for children up to the age of 14, scholarships for deserving students from low-income families, and subsidized housing for the poor.
Poverty is a societal ill, but we can help to combat it. For example, we may easily contribute old clothes to the needy, fund a poor child's education, or volunteer to educate impoverished pupils in our spare time. Before you throw food out, keep in mind that someone is still hungry.
Which of the following best describes a weak acid?
A. It dissociates completely and produces OH- ions in water.
B. It only partially dissociates and produces H+ ions in water.
C. It dissociates completely and produces H+ ions in water.
D. It only partially dissociates and produces OH- ions in water.
Answer:
B.
Explanation:
weak acids - partially dissociate to give H+
strong acids - fully dissociate to give H+
What solution does ?
Students conducting a lab investigation are given two unknown tubes of colorless aqueous solutions. The students are told that one tube is a salt solution and the other is a sucrose solution. How can the students determine which of the solutions contains salt?
The students can determine which of the solutions contains salt through the conductive tester.
What is an ionic solution?It is a solution containing ions are atoms that have gained or lost electrons to acquire a positive (lost electron) or negative (gained electron) charge.
An ionic solution would be able to conduct electricity whereas the covalent would not so if you have a conductivity tester which is available in most labs.
The students can distinguish between the 2 solutions through the conductive tester.
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The volume of a gas filled balloon is 22L at 313K and 1.5 atm. What would the volume be at 273K and 1 atm?
Answer:
28L
Explanation:
V1 = 22L V2 = ?
T1 = 313K T2 = 273K
P1 = 1.5atm P2 = 1.0atm
Using the combined gas law equations;
[tex]\frac{P1V1}{T1}= \frac{P2V2}{T2}[/tex]
∴[tex]V2 = \frac{P1V1}{T1} * \frac{T2}{P2}[/tex]
= [tex]\frac{1.5*22}{313} * (\frac{273}{1})[/tex]
V2 = 28L
From the calculations and the statement of the general gas equation, the volume of the gas becomes 28.8 L
What are gas laws?The gas laws are used to show the relationship between the variables in problems that has to do with gases.
In this case, we have to apply the general gas law as follows;
P1V1/T1 = P2V2/T2
P1V1T2 = P2V2T1
V2 = * 22L * 1.5 atm * 273K/313K * 1 atm
V2 = 28.8 L
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How many moles are in 0.50 g sodium bromide
A block has a length of 9.50mm, width 10.25mm, and height of 50.80 mm. If its mass is 38.7322 grams , what is the density in gram/cm³
Answer: 7.82999 g/cm³
Explanation:
1. Divide all of the lengths of the block by 10 to get them from mm to cm
2. Calculate volume of box
3. Calculate density using volume and mass
1. 24.76 grams of potassium carbonate (K2CO3) is reacted with an excess of aluminum nitrate (Al(NO3)3) to produce potassium nitrate (KNO3) and aluminum carbonate (Al2(CO3)3). How many grams of the product Al2(CO3)3 is formed? Round to the nearest hundredth.
Excess reagents are the chemical species that remain after the reaction completion. 14 gms of aluminum carbonate will be formed.
What are grams?Grams are the unit of the mass that is defined by the product of the moles and the molar mass of the substance.
The balanced chemical reaction is shown as:
3 K₂CO₃ + 2 Al(NO₃)₃ → Al₂(CO₃)₃ + 6 KNO₃
From the reaction, it can be said that 2 moles of aluminum nitrate are required to produce a mole of aluminum carbonate.
Moles of potassium carbonate are calculated as:
Moles = 24.76 gm ÷ 138.205 g/mol = 0.179 moles
If 3 moles of potassium carbonate produce 1 mole of aluminum carbonate, then 0.179 moles will produce 0.059 moles.
From the moles, mass is calculated as:
Mass = moles × molar mass
= 0.059 moles × 234.08 g/mol
= 13.97 gms
Therefore, 14 gms of aluminum carbonate will be formed.
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Use the equation to answer the following question.
2H₂ + O₂ → 2H₂O
How many grams of H₂O are produced from 64.0 g of O₂?
O A. 72.1 g
Answer:
rsghkm vumm
Explanation:
el correo de confirmación con la que se ha enviado desde correo ok recibido gracias saludos María del Ca
1. Once tissue fluid enters the lymphatic capillaries, it is called what?
Lymph
Ducts
Organs
Nodes
a gas sample has a total pressure of 1.7atm. if the sample contains 2 gases and 1 gas has pressure of 0.7 atm, what is the pressure exerted by the other gas?
Answer:
1 atm
Explanation:
The other gas exerts the remaining pressure
1.7 - .7 = 1 atm
how many moles of o2 are needed to produce 34.7g of fe203
Answer:
5.09 moles of Fe is required to react with 3.82 moles of O₂.
0.326 moles of O₂ are needed to produce 34.7 grams of Fe₂O₃.
Reaction stoichiometry
In first place, the balanced reaction is:
4 Fe + 3 O₂ → 2 Fe₂O₃
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
Fe: 4 moles
O₂: 3 moles
Fe₂O₃: 2 moles
The molar mass of the compounds is:
Fe: 55.85 g/mole
O₂: 32 g/mole
Fe₂O₃: 159.7 g/mole
Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
Fe: 4 moles ×55.85 g/mole= 223.4 grams
O₂: 3 moles ×32 g/mole= 96 grams
Fe₂O₃: 2 moles ×159.7 g/mole= 319.3 grams
Moles of Fe needed
The following rule of three can be applied: If by stoichiometry of the reaction 3 moles of O₂ react with 4 moles of Fe, 3.82 moles of O₂ react with how many moles of Fe?
moles of Fe= 5.09 moles
Finally, 5.09 moles of Fe is required to react with 3.82 moles of O₂.
Moles of O₂ needed
The following rules of three can be applied: If by reaction stoichiometry 319.3 grams of Fe₂O₃ are formed from 3 moles of O₂, 34.7 grams of Fe₂O₃ are formed from how many moles of O₂?
moles of O₂= 0.326 moles
Finally, 0.326 moles of O₂ are needed to produce 34.7 grams of Fe₂O₃.
Explanation:
2. An industrial process wastewater contains a mixture of metal fragments and sand. The metal fragments range in diameter from 0.5 to 10 mm with a specific gravity of 1.65. The sand particles range in diameter from 0.04 to 2.0 mm with a specific gravity of 2.65. The wastewater discharge rate is 1400 m3/d at 20°C. Design a settling tank to remove all the metal and sand particles. If the depth of the tank is 2 m, calculate the detention time. Solution Given
The detection time when an industrial process wastewater contains a mixture of metal fragments and sand is 1392.8 seconds.
How to calculate the detection time?From the information regarding the industrial process wastewater, the settling velocity for the sand particles will be:
= 9.81/[18(1.002 × 10^-6] × (2.65 - 1) × (0.04 × 10^-³)²
= 0.001435
Therefore, the detection time will be:
t = 2/0.001435
t = 1392.8 seconds.
The detection time is 1392.8 seconds.
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Which of the following best describes science?
A. The use of experiments and investigations to form opinions
B. The study of the natural world in order to formulate answers to
untestable questions
C. The use of observations and experiments to answer questions
about the natural world
D. The study of the universe to answer philosophical questions
Answer:
c
Explanation:
Science is best described as a way of building knowledge about the world around us through observation and experimentation.
Which statement is correct for the element of proton number 19?
A It is a gas that dissolves in water
B It is a hard metal that is not very reactive with water
C It is a non-metal that burns quickly
D It is a soft metal that is highly reactive with water
Answer:
D
Explanation:
From periodic table : proton number 19 corresponds to K (potassium)
which is very reactive with water
