Answer:
1.T
2.T
3.T
4.F
5.F
6.T
7.T
8.F
9.T
10.T
11.F
12.S
13.T
maaf kalo salah
the epa threshold for acceptable levels of lead ions in water is <15 ppb . what is the molarity of an aqueous solution with a concentration of 15 ppb ?
Molarity of an aqueous solution is 15ˣ10⁻⁷M. if the concentration of an aqueous solution 15ppb.
Molar concentration or Molarity is characterized as the quantity of moles of solute present in an unmistakable measure of liters of the arrangement, that is to say, moles per liters of an answer.
The term Molality was first found in a distribution that goes by the name "Thermodynamics and the Free Energies of Compound Substances", which was distributed in the year 1923 by G N Lewis and M Randall. It is represented by 'm'.
Molarity is the computation of the quantity of solutes that are available in a liter of an answer. As we have referenced before, an answer contains both the solute and the dissolvable. Though, Molality is the estimation of the quantity of solutes that are available in a kilogram of the dissolvable itself. As we definitely know, a dissolvable is something that breaks down the solute.
Now, we are given concentration of aqueous solution is 15ppb,which means in 1 billion number of moles of lead ions are 15
∵In 1 billion ml number of moles of lead ions are =15
∴In 1000 ml number of moles of lead ions are =(15×1000) / 10¹⁰
=>In 1000 ml number of moles of lead ions are=15ˣ10⁻⁷
Hence, molarity of aqueous solution is 15ˣ10⁻⁷M.
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a parent nucleus 82x227 decays 6 particles and 5 electrons (e-). what then is the z value for the daughter nucleus y?
There can be emissions of radiations like gamma radiation. There can be emission of particles too like alpha particle. Therefore, the z value for the daughter nucleus y is 14.5.
What is nuclear decay?Nuclear decay is process in which the radioactive element releases particles or radiations. Alpha particles is ⁴₂He. Alpha particle is nothing but helium particle.
₈₂²²⁷X[tex]\rightarrow[/tex] 6 Y + 5 ⁰₋₁e
total atomic number on left side= total atomic number on right side
82= 6(atomic number of Y)+5(-1)
82=6(atomic number of Y)-5
87=6(atomic number of Y)
atomic number of Y= 14.5
Therefore, the z value for the daughter nucleus y is 14.5.
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For 2 hours, Leah was driving east at one-half of her car's top speed. Her car can go at a maximum speed of 180 kilometers per hour. In this time, how far did Leah drive?
Answer:
180 kilometers in 2 hours.
Explanation:
To find the distance Leah drove, we need to first determine her average speed. Since Leah was driving east at one-half of her car's top speed, her average speed was 180/2 = 90 kilometers per hour.
Next, we can use this speed to determine the distance she traveled. Since Leah was driving for 2 hours at an average speed of 90 kilometers per hour, she traveled 2 * 90 = 180 kilometers.
Therefore, Leah drove 180 kilometers in 2 hours while driving east at one-half of her car's top speed.
What bacteria grows in juice?
The most common bacteria found in juice are Listeria monocytogenes, Escherichia coli, Salmonella, and Staphylococcus aureus.
What is Bacteria?
Bacteria are single-celled microorganisms that exist in their millions, in every environment, both inside and outside other organisms. Bacteria are the most diverse group of organisms on earth, and are believed to be one of the earliest forms of life. They can cause diseases, but can also be beneficial to humans, such as by producing food and vitamins, breaking down organic matter, and helping the body digest food.
Bacteria grows in juice because juice typically contains organic matter and moisture, which provide nutrients and an environment in which bacteria can thrive. Additionally, some types of juice may contain natural sugars and other ingredients which can further encourage bacterial growth.
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How do you convert MgO to Mg?
Magnesium oxide (MgO) can be converted into Mg by reducing MgO with help of carbon.
The balanced chemical reaction for the above reaction is given as:
MgO (s) + C (s) → Mg (s) + CO (g)
Lets check if the reaction is spontaneous,
ΔGο = ΔHo − TΔSo
ΔGo = 491.18 − 298 × [197.67×10⁻³]
ΔGo = 432.27kJ
Thus reaction is non-spontaneous at 298K. For spontaneous nature
ΔGo = −ve i.e., TΔSo > ΔHo
or T × [197.67×10⁻³ ] > 419.18
or T > 491.18 / 197.67 × 10⁻³ > >2120.6K
Hence, MgO can be reduced to Mg by using C at T more than 2120.6K.
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Why RMS value is calculated?
RMS value is calculated because it helps to find the effective value of AC (voltage or current).
What is RMS value?In science and its applications, the root mean square of a bunch of numbers is characterized as the square foundation of the mean square of the set. RMS, likewise called root mean square, is an extraordinary instance of summed up mean. The RMS worth of a ceaselessly changing capability can be characterized as the fundamental of the square of the momentary worth more than one cycle.
For AC current, RMS rises to the worth of steady DC current that delivers a similar power utilization with a resistive burden. In assessment hypothesis, the root mean square mistake of an assessor is a proportion of the defect of the assessor's fit to the information.
RMS value is calculated because it helps to find the effective value of AC (voltage or current).
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What do you think a ion is
A(n) _____ is the smallest particle of an element that retains its identity in a chemical reaction.
Answer:
atom
Explanation:
This describes an ATOM
Is pewter OK in water?
Although frequent handling and living near seawater can cause pewter to oxidize and discolor, pewter does not tarnish like silver and copper. Warm, soapy water can be used to clean pewter. After rinsing, the metal can be towel dried.
In water, is pewter safe?Lead-free and secure to use, modern pewter. It is primarily comprised of tin, with some antimony and copper. The goods are guaranteed to be lead-free and are perfectly safe to be used for all types of food and beverages, claims one maker.
Lead content in antique pewter?30 percent lead and 70 percent tin were the main components of ancient pewter. With time, this pewter, sometimes known as black metal, darkened significantly, and lead rapidly leached out when it came into touch with acidic foods.
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The molecular geometry (shape) of the PF4+ ion IS tetrahedral trigonal planar trigonal bipyramidal octahedral trigonal pyramidal Using VSEPR Theory, the predicted Cl-B-Cl bond angle for BCI3 is 180° 107° 120° 109.5° 900 Using VSEPR Theory the molecular geometry (shape) for SF4 is square planar trigonal bipyramidal T-shaped octahedral see-saw
According to the modern VSEPR theory, the shape of [tex]PF^{+}_4[/tex] is Tetrahedral. The predicted Cl - B - Cl bond angle forming [tex]BCl_{3}[/tex] is 120°. The molecular geometry (shape) of [tex]SF_{4}[/tex] is See-saw.
According to the modern VSEPR theory, we can calculate geometry(shape) by calculating the valence electrons.
number of electron - shape
6 - Trigonal
8 - Tetrahedral
10 - Trigonal bipyramidal (TBP)
12 - Octahedral
a. [tex]PF^{+}_4[/tex]
Here, the total valence electrons = 5 + 4 - 1 = 8.
valence electrons of P = 5
Valence electrons of F = 1.
hence, we get the total F = 4.
So, the number of valence electrons is 8. So the shape is Tetrahedral.
b. [tex]BCl_{3}[/tex]
Here, the total valence electrons = 3 + 3 = 6.
this means that the shape is trigonal planar.
So, the predicted Cl - B - Cl bond angle forming [tex]BCl_{3}[/tex] is 120°.
c. [tex]SF_{4}[/tex]
Here, the total valence electrons = 6 + 4 = 10.
valence electrons of P = 6
Valence electrons of 4 F = 4.
So, the number of valence electrons is 10. So the shape is Trigonal Bipyramidal (TBP).
Geometry is TBP according to VSEPR but the shape is see-saw according to Bents rule.
Check out the molecular geometry (shape) given below.
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What is the percent composition of a compound formed when 4.96 g of bromine combines with lithium to form 5.39 g of lithium bromide?
The percent composition of lithium bromide is 91.9% bromine and 8.1% lithium.
This can be calculated by dividing the mass of each element in the compound by the total mass of the compound, and then multiplying by 100 to get the percent composition.
For bromine, the mass is 4.96 g and for lithium, the mass is 0.43 g.
Therefore, the percent composition of bromine is (4.96/5.39) x 100 = 91.9%, and the percent composition of lithium is (0.43/5.39) x 100 = 8.1%.
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What is the maximum amount of sugar that will completely dissolved in 20 mL of water?
To get a saturated solution, we must dissolve 200 divide by 100 multiply by 20 grams of sugar in 20 l of water. The alternative to this statement is 40 grams of sugar.
Describe saturated solution and provide an example.The highest concentrations of an immediately following in the solvent is called a saturated solution, and any more solute will not breakdown in a liquid medium. Example: A sugar solution.
What causes a saturated solution to form?The sodium ions leave the exterior of the solids when a solvent containing the solute is added, becoming solvated by the solution and initially creating an imbalanced solution. The solution reaches saturation when the maximum amount of solute that can dissolve has done so.
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What temperature does PVC pipe?
PVC pressure pipe should be operated at a maximum temperature of 140°F. PVC pipe and culvert stiffens as temperature drops and becomes more flexible as temperature rises. Published pipe stiffness figures, like dimensions as well as pressure capacity, are only valid for 73°F temperature applications.
What is PVC?Polyvinyl chloride is the third most widely manufactured polymeric material of plastic in the world. Every year, around 40 million metric tonnes of PVC are produced. PVC is classified into two types: rigid and flexible. PVC rigid is used in building projects for pipe and profile applications like doors and windows.
What kind of plastic is PVC?PVC, the third most common synthetic plastic polymer, can be manufactured with rigid or versatile properties. Its ability to meld with other materials is well-known.
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. Calculating Methane reacts with oxygen is the following combustion reaction.
CH4 +202——>CO₂ + 2H₂O
What bonds are broken when one molecule of methane reacts with two molecules of oxygen?
-I DON’T UNDERSTAND THIS
The connection among hydrogen and carbon was broken when one molecules of gas (methane) reacted with two molecule of oxygen in a specific process.
Where can you find methane?Massive natural sources of gas include termite digestion, emission from wetlands and seas, and ocean currents. Production of rice, landfills, raising of cattle and other reproductive animals (cow burps! ), and energy production are examples of sources linked to human activity.
How dangerous is methane?Methane was non-toxic and poses no danger when inhaled in small amounts, but if significant amounts of the gas are allowed to replace air, the lack of oxygen could cause suffocating.
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Why is it always cooler by the water on a hot sunny day
Answer:
Explanation:
Well put simply, all our beautiful lakes this time of year are cold after a long winter. If you are enjoying a nice sunny, warm calm day, then the temperature drops 20 degrees as a breeze swings in from the lake, we call that a lake breeze. You can blame the specific heat as to why that occurs. Specific heat is defined by the amount of energy required to raise a unit of mass of a substance by a degree. For our purposes it is how much heat energy it takes to raise the same amount of water as it does land.
balance the reaction equation with the lowest set of whole number coefficients. what is the coefficient (d) of h2o? a c4h10 b o2 ---> c co2 d h2o
The coefficient for the balanced chemical equation 2C4H10 + 13O2 ---> 8CO2 + 10H2O is 10.
Every chemical equation can be balanced by following some simple steps and rules.
- Count any element on both sides, while paying attention to all numbers that modify this element’s count in a certain occurrence. If one side has fewer of this element than the other one, add multipliers in front of the molecules that contain this element.
- Go back to step one and repeat with a different element. In complicated cases, you might need to do an element twice or even more often.
- When you are sure everything is balanced, look at the equation again and try to find a greatest common divisor among all multipliers.
so following these rules, we got the stoichiometrically balanced equation.
2C4H10 + 13O2 ----> 8CO2 + 10H2O
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What kind of bond is this?
When two elements share 2 pairs of electrons between them. So each element gives the other element 2 electrons, so there are 4 electrons total being shared between the two elements. What sort of bond is this?
a double covalent bond
b single covalent bond
c polar covalent bond
d quadruple covalent bond
Answer:
a double covalent bond
Explanation:
Why is ethane rarely used as a fuel?
Answer:
its because due to The lack of awareness is the major barrier for using ethane as a transportation fuel.
Explanation:
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50 Points
A sample of hydrogen was prepared and collected over water at 25 °C and a total pressure of 742 torr. It occupied a volume of 288 mL. Calculate its partial pressure (in torr) and what its dry volume would be (in mL) under a pressure of 1.00 atm.
The partial pressure of the hydrogen is 718.24 torr
The volume of the hydrogen is 273.6 mL
What is the partial pressure?We know that the partial pressure is the pressure of a gas that is part of a mixture of gases. Following the law of the partial pressures, it is clear that the number of gases that can be mixed would give rise to the combination of gases that we can call a mixture of gasses.
The total pressure of the mixture of gases can be obtained by the use of the formula that was deduced from the Dalton's law of partial pressures.
Vapor pressure of water in torr = 23.76 torr
Partial pressure of the hydrogen = 742 torr - 23.76 torr
= 718.24 torr
Pressure in atm = 0.95 atm
From the Boyle's law to get the volume;
[tex]P_{1}[/tex][tex]V_{1}[/tex] = [tex]P_{2}[/tex][tex]V_{2}[/tex]
[tex]V_{2}[/tex] = 0.95 atm * 288/1.00 atm
[tex]V_{2}[/tex] = 273.6 mL
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How do you test if something is an ionic compound?
Answer:
The most simple way to identify an ionic compound is to check if the chemical compound is made of just two elements wherein one element can be a metal (belonging to any groups 1, 2 or 3) and the second element is a non-metal, (from group 5, 6 or 7).
Explanation:
18) Match the appropriate benefit of dietary fiber intake to its associated disease. (Use each choice only once). Cardiovascular Disease A. Lowers Blood Cholesterol Hypertension B. Lowers Blood Pressure Type 2 Diabetes c. Decreases intestinal transit time and exposure to potential toxins D. Slows absorption of glucose Constipation Obesity E Slows rate of digestion, promotes satiety Colon Cancer F. Increases fecal bulk & promotes regularity
Appropriate benefit of dietary fiber intake to its associated disease.- c. Decreases intestinal transit time and exposure to potential toxins
Cardiovascular diseases (CVDs) are the most common cause of death worldwide, claiming the lives of an estimated 17.9 million persons each year. CVDs are a group of heart and blood disorders that include coronary artery disease, vascular disease, rheumatic fever, and others. Coronary heart disease could be cured, but treatment can help manage the symptoms and lower the risk of conditions such as heart attacks. Treatment may include changes in lifestyle, such as physical activity and quitting smoking. The most common symptom of heart disease is heart disease (CHD), which kills approximately 382,820 people every year. Every year, approximately 805,000 Americans suffer a heart attack.
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how many moles of c12h22o11 are needed to prepare 2.50 l of 0.300 m solution. 0.750 moles 0.430 moles 8.33 moles 1.20 moles
0.750 moles of C12H22O11 are needed to prepare 2.50 L of a 0.300 M solution.
Molarity is a measure of concentration that can be used to determine how many moles of a particular substance are needed to prepare a given volume of a solution with a given concentration. In this problem, we are asked to calculate how many moles of C12H22O11 are needed to prepare 2.50 L of a 0.300 M solution.
To solve this problem, we will first use the molarity equation, which states that molarity (M) is equal to the moles of solute (n) divided by the volume of solution (V):
M = n/V
We can then rearrange the equation to calculate the number of moles of solute needed to prepare a given volume of solution with a given molarity:
n = M x V
Plugging in the values from the problem, we get:
n = 0.300 M x 2.50 L
This yields a result of 0.750 moles of C12H22O11 needed to prepare 2.50 L of a 0.300 M solution.
Alternatively, if we were given the moles of solute needed to prepare a given volume of solution with a given molarity, we could use the molarity equation to calculate the molarity of the solution. For example, if we were given that 0.430 moles of C12H22O11 are needed to prepare 2.50 L of a solution, then we could calculate the molarity of the solution as follows:
M = n/V
M = 0.430 moles / 2.50 L
This yields a result of 0.172 M.
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The following
compound, lited with their boiling
point, are liquid at -10°C: butane, -0. 5°C;
ethanol, 78. 3°C; toluene, 110. 6°C. At -10°C,
which of thee liquid would you expect to
have the highet vapor preure? Which the
lowet? Briefly explain
The given question is incomplete, and hence, can not be answered. Still, adding some relevant information for your reference.
What is vapor pressure?
Vapor pressure , or equilibrium vapor pressure, is the pressure produced by a vapor in thermodynamic equilibrium with a condensed phase (solid or liquid) at a given temperature. Defined as applied pressure. temperature in a closed system. Equilibrium vapor pressure is a measure of the evaporation rate of a liquid. This refers to the tendency of particles to escape from liquids (or solids). Substances that have a high vapor pressure at room temperature are often called volatile. The pressure that vapor exerts on the liquid surface is known as vapor pressure. As the temperature of a liquid increases, so does the kinetic energy of its molecules. As the kinetic energy of the molecules increases, the number of molecules that become vapor also increases, increasing the vapor pressure.
The given question is incomplete, and hence, can not be answered. Still, adding some relevant information for your reference.
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The loss of a beta particle by a radioactive nuclide causes an INCREASE in the atomic number. True or False?
Answer:
False
Explanation:
Beta particles are electrons...which do not affect the atomic number...losing a beta particle will not change the atomic number.
The atomic number is determined by the number of PROTONS in the matter.
( ALPHA particles will change the atomic number as they have protons in them)
Conductivity level probes can only be used with conductive liquids.
a. True
b. False
Conductivity level probes can only be used with conductive liquids.
a) True
The conductivity probe is the level of point measuring system consist of two or more probes or electrodes or electrodes and vessel ,the material in the vessel completes the circuit when the level will rise in the vessel. A probe is the insertable device which have the sensor. the conductive liquids are that are the solution of the acids , the bases and the salts. sugar solution and the distilled water are poor conductors.
Thus, it is true that , Conductivity level probes can only be used with conductive liquids.
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A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given
temperature.
3H2 + N2 2NH3
An analysis of the mixture at equilibrium revealed 2.1 mol N2, 3.2 mol H2, and 1.8 mol NH3.
How many moles of H2 were present at the beginning of the reaction?
A) 3.2
B) 4.8
C) 5.0
D) 5.9
E) 4.4
The number of moles of the hydrogen at the beginning is 5.0. Option C
What is the amount of the hydrogen gas at the beginning?In this case, we have that the system does include the hydrogen gas, the nitrogen gas and the ammonia gas. The analysis of the mixture has shown the amount of each of the species that we have at equilibrium.
All we need to do is to look at the amount of the ammonia that we have at the point of equilibrium and this would give us the value of M. We would then have that at equilibrium;
3.2 = M - (1.8)
M = 3.2 + (1.8)
M = 5.0
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Culinary emulsion can disperse fat into the water, but it cannot disperse water into the fat.
a. True
b. False
Culinary emulsion can disperse fat into the water, but it cannot disperse water into the fat. The sentence is True.
The two types of culinary emulsions are fat dissolved in water and water dissolved in fat. The emulsions of fat and water that are most frequently used are hollandaise, mayonnaise, aioli, milk, and pan sauces. The most typical forms of water in fat emulsifications are vinaigrettes and whole butter. The vinaigrette is made by mixing vinegar and oil. Mayonnaise is typically made with egg yolks and oil. Aioli is made with garlic and oil. Milk sauces can be made with any type of milk, but are mostly commonly seen in cream sauces. The fat in butter is emulsified with water. The butter is created when the butterfat is emulsified with salt and water.
Therefore, the given statement is right.
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Answer: its false
Explanation: got it right on test
Define boiling point and melting point.
Answer:
The boiling point is the temperature at which a liquid boils and changes into a gas. At the boiling point, the vapor pressure of the liquid is equal to the atmospheric pressure.
The melting point is the temperature at which a solid changes into a liquid. At the melting point, the solid and liquid phases are in equilibrium and the substance can exist in either phase.
The boiling point and melting point of a substance depend on the intermolecular forces between the molecules in the substance. Substances with strong intermolecular forces, such as covalent compounds, tend to have higher boiling points and melting points than substances with weaker intermolecular forces, such as ionic compounds. The boiling point and melting point of a substance also depend on the pressure under which the substance is being heated or cooled. For example, the boiling point of water is lower at high altitudes, where the atmospheric pressure is lower.
The two solids are similar and the ratio between the lengths of their edges is 2 7.
The ratio of the surface areas of The two solids are similar and the ratio between the lengths of their edges is 2:7 is 4:49
The ratio of the surface area can be calculates as follows:
The fact that
The scale factor is the ratio between the equivalent sides of two figures that are similar to one another.
The scale factor in this question is equal to the ratio 2
7
and
Acknowledge this
When two solid are similar, their surface area ratios are equal to the square of the scale factor.
therefore,
The ratio of their surface areas in this question is (2/7)² = 4/49
Your question is incomplete but most probably your full question was
The two solids are similar and the ratio between the lengths of their edges is 2:7 what is the ratio of their surface areas?
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How do you find the pH of a HBr solution?
Therefore, the pH of the solution is -9 + log([HBr]/[HBr]) = -9 + log(1) = -9.
What is solution?Solution is a term used to describe the answer or resolution to a problem, challenge, or inquiry of some kind. It is an act or means of solving a problem or reconciling differences. A solution may also involve setting a goal or plan of action to reach the desired outcome. Solutions are often creative and require collaboration from multiple individuals or groups. Solutions can also be found in the form of products, services, or information.
The pH of a HBr solution can be found by using the Henderson-Hasselbalch equation, which states that pH = pKa + log([salt]/[acid]). In this case, the pKa of HBr is -9 and the molar concentration of HBr is [HBr].
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