A newly discovered element, Y, has two naturally occurring isotopes. 90.3 percent of the sample is an isotope with a mass of 267.8 u, and 9.7 percent of the sample is an isotope with a mass of 270.9 u. What is the weighted average atomic mass for this element? 269.4 u 268.1 u 269.0 u 270.6 u
Answer: 268.1 u
Explanation:
Mass of isotope 1 = 267.8 u
% abundance of isotope 1 = 90.3% = [tex]\frac{90.3}{100}=0.903[/tex]
Mass of isotope 2 = 270.9 u
% abundance of isotope 2 = 9.7% = [tex]\frac{9.7}{100}=0.097[/tex]
Formula used for average atomic mass of an element :
[tex]\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}\times {{\text { fractional abundance}})[/tex]
[tex]A=\sum[267.8\times 0.903+270.9\times 0.097][/tex]
[tex]A=268.1u[/tex]
Therefore, the average atomic mass of an element is, 268.1 u
The United States is one of the few countries in the world which has not yet adopted the metric system for general use. True or False
The presence of water will ________ the melting temperature of a rock.
What is the volume of 0.0775 mole of nitrogen if the molar volume is 27.6 l/mol?
When does water act as an acid and a base?
Water can donate a proton to become a hydronium ion or hydroxide ion.
Water can accept a proton to become a hydronium ion, or donate a proton to become a hydroxide ion.
Water can accept a proton to become a hydronium ion or a hydroxide ion.
Water can donate a proton to become a hydronium ion, or accept a proton to become a hydroxide ion.
A horizontal row ( → ) of elements on the periodic table may also be referred to as a:
Identify the correct formula for Beryllium Phosphate.
Question options:
Be3(PO4)2
Be2(PO4)3
Be(PO4)2
BePO4
The correct formula for beryllium phosphate is Be(PO4)2. Therefore option 3 is correct.
Beryllium phosphate is composed of the element beryllium (Be) and the phosphate ion (PO4). In the phosphate ion, there is one phosphorus atom (P) bonded to four oxygen atoms (O), forming a polyatomic ion with a -3 charge.
To write the formula for an ionic compound, we need to balance the charges of the ions. Beryllium has a +2 charge (Be2+) and the phosphate ion has a -3 charge (PO43-).
In order for the compound to be electrically neutral, we need two beryllium ions to balance the charge of three phosphate ions:
2(Be2+) + 3(PO43-) = Be(PO4)2
Thus, the correct formula for beryllium phosphate is Be(PO4)2.
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What is the main chemical compound cells use for energy?
What is the percent by mass of water in Na2SO4 • 10H2O?
Use mc003-1.jpg.
5.59%
11.26%
44.08%
55.92%
The answer is 55.92%
Answer : The correct option is, 55.92 %
Solution : Given,
Molar mass of [tex]Na_2SO_4.10H_2O[/tex] = 322 g/mole
Molar mass of water = 18 g/mole
The mass of [tex]10H_2O[/tex] = [tex]10\times 18=180g[/tex]
Now we have to calculate the percent by mass of water in [tex]Na_2SO_4.10H_2O[/tex]
Formula used :
[tex]\text{Percent by mass of water}=\frac{\text{Mass of}10H_2O}{\text{Mass of }Na_2SO_4.10H_2O}\times 100=\frac{180g}{322g}\times 100=55.92\%[/tex]
Therefore, the percent by mass of water in [tex]Na_2SO_4.10H_2O[/tex] is, 55.92 %
what is the ratio of fe3+ ions to o2- in a neutral compound?
Potassium and oxygen will combine to make a compound. K_O_ Fill in the blanks with the number of the subscript.
did you get the answer? there was two boxes what do i put?
Which procedure could a student use to examine an intensive property of a rectangular block of wood
Answer:
The correct answer is density, because intensive properties can be measured.
Explanation:
Intensive properties can be measured. Their values depend on the type of material and not the amount of matter we have. To measure density, we must first measure the volume of the block of wood with a measuring tape, then we can weigh the block of wood on a calibrated scale, and finally, calculate density as the ratio of mass to volume ( m/V).
Have a nice day!
Which of the following is a physiological adaptation? a. group hunting b. hyoid bone adapted for roaring c. dark coloration d. migration
Answer:
b. hyoid bone adapted for roaring is the correct answer.
Explanation:
Hyoid bone adapted for roaring is the example of physiological adaptation.
A physiological adaptation is an adaptation and the control of an organism’s internal body state so that it can adapt to its changing conditions.
A physiological adaptation is an organism’s inner response to outside stimuli to maintain homeostasis state.
Physiological adaptations are the physiological changes in an organism that assist them to sustain.
physiologic adjustment improved the ability of an organism to survive with the uncertain environment.
The titration of 25.00 ml a 0.125 m hclo4 solution requires 27.07 ml of koh to reach the endpoint. what is the concentration of the koh
Answer : The concentration of the [tex]KOH[/tex] is, 0.115 M
Explanation :
Using dilution law,
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1[/tex] = basicity of an acid = 1
[tex]n_2[/tex] = acidity of a base = 1
[tex]M_1[/tex] = concentration of [tex]HClO_4[/tex] = 0.125 M
[tex]M_2[/tex] = concentration of KOH = ?
[tex]V_1[/tex] = volume of [tex]HClO_4[/tex] = 25 ml
[tex]V_2[/tex] = volume of NaOH = 27.07 ml
Now put all the given values in the above law, we get the concentration of the [tex]KOH[/tex].
[tex]1\times 0.125M\times 25ml=1\times M_2\times 27.07ml[/tex]
[tex]M_2=0.115M[/tex]
Therefore, the concentration of the [tex]KOH[/tex] is, 0.115 M
The concentration of 27.07ml of KOH solution requires to titrate 25mL of 0.125 M HClO₄ is 0.115 M.
How do we calculate the concentration?Concentration of any solution in the titration will be calculated by using the below equation as:
M₁V₁ = M₂V₂, where
M₁ & V₁ is the molarity and volume of HClO₄ and M₂ & V₂ is the molarity and volume of KOH solution. Now putting values from the question on the above equation, we get
M₂ = (0.125)(25) / (27.07) = 0.115 M
Hence required concentration of KOH is 0.115M.
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Why does a weather balloon filled with Helium rise? (Refer to "Densities of Common Substances" table.)
a) Its density is greater than air.
b) Its density is less than air.
What is the best solution to groundwater depletion?
The best solution to groundwater depletion involves sustainable water management, including water conservation, optimizing irrigation, and using crops that require less water. Strategies like enhancing aquifer recharge, regulating water usage, and using alternative water sources also play a role, supplemented by public education and technological innovations.
Addressing groundwater depletion involves several strategies that could be considered the best solutions depending on the local context. One crucial approach is the implementation of sustainable water management practices. This includes practices such as water conservation, optimizing irrigation efficiency to achieve 'more crop for the drop', selecting crops that require less water, and utilizing virtual water concepts to reduce local water usage. Additionally, managing water reallocation policies and overcoming social, political, and economic barriers can also be integral to addressing groundwater depletion.
Another key solution is enhancing the recharge of aquifers through methods like artificial recharge basins, rainwater harvesting, and the restoration of wetlands which naturally replenish groundwater. Protecting aquifers from overuse by regulating well drilling and pump installation can prevent groundwater mining, which leads to issues such as land subsidence and saltwater intrusion. In areas where this has already become a problem, tactical reduction in groundwater extraction and the development of alternate water sources, such as desalination of seawater or treated wastewater, can provide relief and time for aquifers to recover.
Public education campaigns aimed at water conservation and the importance of preserving water resources are essential for fostering community support for long-term sustainable water management. Moreover, the integration of technology to monitor and manage water resources, and investment into research to develop drought-resistant crops and innovative water-saving technologies can have a substantial impact on reducing groundwater depletion.
0 points what is [h3o +] in a solution made by dissolving 0.200 mole of sodium acetate (nach3coo) in enough water to make one liter of solution?
A Helium Balloon contains 24.3 moles of Helium Gas. How many grams of Helium is this?
0.165 g
6.01 g
97.2 g
1.46 x 10^25 g
Answer:
C) 97.2g
Explanation:
Information given;
- Calculate Number of moles
- Mass of Helium
Before proceeding, it is important to know the relationship between number of moles, mass and molar mass.
Generally 1 mole of a atom weighs as much as its molar mass. Given that the molar mass of Helium is 4.00g/mol.
It means one mole of Helium weighs 4 g.
How grams then do 24.3 moles weigh?
1 mol = 4.00g
24.3 mol = x g
Cross multiplication yields;
x = (24.3 * 4) / 1
x = 97.2 g
Which mass law(s) is/are demonstrated by the observation that a sample of potassium chloride from chile contains the same percent by mass of potassium as one from poland?
a. law of conservation of mass
b. law of definite composition
c. law of multiple proportions
d. laws of conservation of mass and definite composition
e. laws of conservation of mass and multiple proportions?
The correct answer is b. Law of Definite Composition.
Further ExplanationA) Law of Conservation of Mass
FALSE. This law describes the masses of substances before and after a reaction as constant. Atoms only rearrange in during chemical reactions. None is destroyed nor are any new atoms created. Therefore, the total mass of reactants must always be equal to the total mass of the products.
B) Law of Definite Composition
TRUE. Sometimes called the Law of Constant Composition, this law states that regardless of the source of a compound, its composition is the same. The mass percentages of the elements that make up a particular compound is constant. KCl, in the example, will always have 1 mol of potassium ions and 1 mole of chloride per mole of the potassium chloride regardless of whether it was from Chile or Poland.
C) Law of Multiple Proportion
FALSE. This law describes how an element combines with another element to form multiple compounds. The ratio at which they combine are in whole numbers.
D) Law of Conservation of Mass and Definite Composition
FALSE. The Law of Conservation of Mass pertains to what happens to masses of substances before and after a chemical reaction. This problem is about different sources of a compound and not about a specified chemical reaction.
E) Law of Conservation of Mass and Multiple Proportions
FALSE. The problem is about the mass percentage of compounds from different sources, not about the reaction of the compound nor other compounds formed by potassium and iodine.
Learn MoreBalancing Equations https://brainly.com/question/2396833Mass Percentage https://brainly.com/question/11085567Keywords: Law of Definite Proportion, Law of Constant Composition
Laws gave ideas about conservation, composition, and proportions. The same percent by mass of the potassium in the sample indicates the law of definite composition. Thus, option b is correct.
What is the law of definite composition?The law of definite composition states the constant composition of the chemical compound irrespective of the place they are. The ratio of the element in the compound does not vary because of the source and preparatory methods.
The sample of potassium chloride will have the same proportion of potassium in both Chile and Poland as it is a fixed ratio that does not depend on the source. It ensures the uniform preparation of the chemical compound.
Therefore, the sample will have the same proportion of potassium due to the law of definite composition.
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A compound contains 71.24 g carbon per 100.0 g compound and has a molar mass of 202.32 g/mol. determine the value of the subscript for carbon in the compound. enter answer as an integer.
Answer:
The answer is 12
Explanation:
Carbon has a relative atomic mass of 12. The Carbon content of the compound is 71.24 out of 100 and the molecular mass of the compound is 202.32g/mol. Therefore the amount of Carbon in the entire compound is 71.24/100 * 202.32 =144.132768g.
Since one one carbon is 12g, then, 144.133g will approximately be 12*12. Hence the subscription will be 12.
What are the most reactive metals found on the periodic table?
Some of the oldest rocks ever found have been estimated to be about 3.5 billion years old. Is it likely that these rocks were present when Earth was first formed?
a. No, rock material is constantly recycled on Earth as rock is melted into magma.
b. Yes, most of the rocks on Earth can be dated back to the time when Earth was first formed.
c. No, this rock is probably just a sedimentary rock that was formed by much younger igneous rocks.
d. No, it is likely that any rocks older than a few hundred years are meteorites from outer space.
the answer is A. no, rock material is constantly recycled on earth as rock is meted into magma
the weight of an object is constant. true false
What precautions must be taken when handling 0.5 m hcl and 0.3m koh solutions in the laboratory?
The precautions we take to handle these solutions is to wear safety goggles, lab coat and also the hand gear (this is also important).
KOH (potassium hydroxide), which is a strong base and HCL (hydrochloric acid) which is a strong base and both these solutions dissociates completely in water. So, whenever you are working in laboratory with chemicals you must be careful.
Which of the following is the best name for SO3?
a. sodium trioxide
b. sulfur trioxide
c. monosodium trioxide
d. monosulfur trioxide
Answer: Option (b) is the correct answer.
Explanation:
Since the given substance is [tex]SO_{3}[/tex], so we can see that there are three oxygen atoms and one sulphur atom.
Therefore, due to three oxygen atoms a prefix 'tri' will be added before the name of oxygen in the name of this given compound or substance.
So, name of cation will be written first and then name of anion will be written.
Therefore, name of [tex]SO_{3}[/tex] is sulfur trioxide.
In the chart, the missing classification term is
A) domain
B) species
C) specimen
D) common name
Kingdom: Animalia
Phylum: Chordata
Class: Marrnalia
Order: Primates
Family: Homindae
Genus: Homo
Sapiens: ?????
Answer:
The Answer is B) species
Explanation:
I just did this on usa test prep and C is wrong
The scientific name of humans is Homo Sapiens. This name is a combination of its genus name Homo and species name Sapiens. Thus the missing classification is species.
What is biological classification?The biological classification for all type of living in the biosphere is introduced by Carl Linnaeus. He classified each type of livings into different classes with 7 categories namely kingdom, phylum, class, order, family , genus and species.
Each category of the classification is based on the structural properties and behaviors of the organisms. Scientific names are provided to each type of organisms to commonly understand them with a standard name.
A scientific name of an organism is the combination of its genus name and species name. The first word is genus name and the second word is its species name.
The genus name of humans is Homo and specie name is Sapiens. Thus, the scientific name is Homo Sapiens. Therefore, the missing classification is species here.
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Elements in the same __________ are similar due to similarities in their number of valence electrons.
Answer:
Elements in the same __group__ are similar due to similarities in their number of valence electrons.
Explanation:
Why will external fluid flow into a plant cell? because the external water concentration is greater because the external water concentration is less because the external salt concentration is greater because the external salt concentration is less?
Under normal conditions, water will move from the solution of lower concentration to the solution of higher concentration. This is called the process of osmosis and is driven by the concentration gradient. So I can identify two answers here:
> because the external water concentration is greater
> because the external salt concentration is less
Hydrogen powered cars create less pollution than gasoline powered cars when driven.What might be a challenge to using hydrogen as a fuel?
Answer:
New fueling stations would have to be built that can handle hydrogen
Explanation:
calculate the average mass of these three samples: 104.2g, 3.21g, 29.0g.
Answer : The average mass of these three sample is 45.47 g
Explanation :
Average : It is defined as the sum of all the values divided by the total number of values.
[tex]\text{Average}=\frac{\text{Sum of all values}}{\text{Number of values}}[/tex]
As we are given the mass of three samples which are, 104.2 g, 3.21 g, 29.0 g
Now we have to determine the average mass of the given sample.
[tex]\text{Average}=\frac{\text{Sum of all values}}{\text{Number of values}}[/tex]
[tex]\text{Average}=\frac{104.2g+3.21g+29.0g}{3}=\frac{136.41}{3}=45.47g[/tex]
Therefore, the average mass of these three sample is 45.47 g