According to an informal 1992 survey, the drinking water in about one-third of the homes in Chicago had lead levels of about 10 ppb. Dr. Koether lived in Chicago from 1996 to 1998. Assuming she drank 1.4 L of water a day, calculate the total amount of lead in mg (using one decimal place) that she was exposed to over the two years if she lived in a home that had such high levels of lead.
Answer:
10.2 mg
Explanation:
Step 1: Calculate the total amount of water she drank
1 year has 365 days and she lived in Chicago for 2 years = 2 × 365 days = 730 days.
If she drank 1.4 L of water per day, the total amount of water she drank is:
730 day × 1.4 L/day = 1022 L
Step 2: Calculate the amount of Pb in 1022 L of water
The concentration of Pb is 10 ppb (10 μg/L).
1022 L × 10 μg/L = 10220 μg
Step 3: Convert 10220 μg to milligrams
We will use the conversion factor 1 mg = 1000 μg.
10220 μg × 1 mg/1000 μg = 10.2 mg
Wet helium gas is placed into a balloon at 24.4 degrees Celsius and a pressure of 765.3 mm Hg. What volume (in L) does the dry gas occupy if the water vapor pressure is 24.3 torr and the mass of dried helium gas in the balloon is 0.498 g
Answer:
Hence the Volume of Gas = 3.04 L.
Explanation:
pressure of dry gas = 765.3 - 24.3 = 741 mmhg
Temperature of gas = 24.4+273.15 = 297.55 k
No of mol of gas = 0.498/4 = 0.1245 mol
R = gas constant = 0.0821 l.atm.k-1.mol-1
From ideal-gas equation
PV = nRT
(741/760) x v = 0.1245 x 0.0821 x 297.55
V = Volume of Gas = 3.04 L
A water chemist measured and recorded the air temperature at 27°C when he should have measured the water temperature, which was only 21°C. As a result of this error, will the dissolved oxygen concentration be reported as being higher or lower than it should be? Explain.
Answer:
See explanation
Explanation:
The dissolution of oxygen in water is exothermic. Hence, at higher temperature, less oxygen is dissolved in water.
If the chemist commits an error and records 27°C instead of 21°C, the dissolved oxygen concentration will be found to be lower than it should be at 27°C because dissolution of gases in water is exothermic.
Most reactions, including enzyme-catalyzed reactions, proceed faster at higher temperatures. However, for a given enzyme, the rate drops off abruptly at a certain temperature. Account for this behavior.
Answer:
It has denatured
Explanation:
When the temperature get high the enzymes tend to change shape and denaturing occurs.
Congratulations! You are now the head biologist at the local "Cells and Bells" research lab! It has come to other cell biologists' attention recently that some cells are too small to contain all of the organelles inside of them. They decide that it's best to get rid of an organelle, but they're not sure which one. In the first process of this decision, they need to know "which organelle is the most important?"
Your job, as the head cell biologist, is to decide which organelle the cell cannot live without.
Write a research paper (intro, body, and conclusion) on which organelle is the most important and why.
11. How many oxygen atoms are there in one formula unit of Ca2+?
Answer:
NO3 has 3 atoms of oxygen in it per molecule (indicated by the subscript of 3) and (NO3)2 means you have 2 NO3 molecules, meaning you double the subscript to get 6 oxygen atoms.
Explanation:
Find the volume occupied by 128g of SO2.
The volume occupied by the given amount of sulfur dioxide will be 84 L.
please show working my dear citizen
What is the purpose of the periotic table?
Answer:
The periodic table was first designed by Mendeleev. It is designed to systematically categorise elements according to atomic number, electron configuration and recurring chemical properties. This allows identification of elements through their characteristics simply by analysing its position on the table.
NEED ANSWER FAST 50 POINTS
A mixture of copper sulfate and water is heated, leaving a residue of copper sulfate in the container. Which method was used to separate the mixture?
A. chromatography
B. evaporation
C. filtration
D. distillation
The method used to separate copper sulfate and water mixture was evaporation.
Explanation:
Chromatography is a separation technique used in labs. In this technique, there are two phases, the mobile phase, and the stationary phase. The phase in which the mixture is dissolved is termed as mobile phase and the phase which serves as a carrier through the system like, sheet, capillary, etc. is termed as mobile phase.Evaporation is a process in which the action of heat is employed to separate dissolved solids from liquid. Due to heat liquid gets evaporated leaving the solid behind.Filtration is a process in which insoluble particles are separated from the liquid by allowing them to pass through a porous substance such as filter paper. Distillation is a process used in the separation of the mixture of liquids with different boiling points.So, from this, we can conclude that the method used to separate copper sulfate and water mixture was evaporation.
Learn more about separation techniques here
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Answer:
Just did this on my test the answer is evaportion.
Explanation:
What is the mass of 7.2 moles of titanium to the nearest tenth?
Answer:
7.2 moles of titanium weigh 344.7 grams.
Explanation:
Molar mass of titanium = 47.88 g
[tex]1 \: mole \: of \: titanium = 47.88 \: grams \\ 7.2 \: moles \: of \: titanium = g[/tex]
solve for g
[tex]g = ( \frac{7.2 \times 47.88}{1} ) \\ g = 344.7 \: grams[/tex]
Answer:
[tex]\boxed {\boxed {\sf 344.7 \ g \ Ti}}[/tex]
Explanation:
We are asked to find the mass of 7.2 moles of titanium.
To convert from moles to grams, we use the molar mass. This value is the mass of 1 mole of a substance. They are equivalent to the atomic masses found on the Periodic Table, but the units are grams per moles instead of atomic mass units.
Look up titanium's molar mass on the Periodic Table.
Ti: 47.87 g/molConvert moles to grams using dimensional analysis. First, set up a ratio using the molar mass.
[tex]\frac {47.87 \ g \ Ti}{1 \ mol \ Ti}[/tex]
We are converting 7.2 moles to grams, so we multiply the ratio by this value.
[tex]7.2 \ mol \ Ti *\frac {47.87 \ g \ Ti}{1 \ mol \ Ti}[/tex]
The units of moles of titanium cancel.
[tex]7.2 *\frac {47.87 \ g \ Ti}{1 }[/tex]
The denominator of 1 can be ignored (a number over 1 is just the number).
[tex]7.2 *47.87 \ g \ Ti}[/tex]
[tex]344.664 \ g \ Ti[/tex]
We are asked to round to the nearest tenth. The 6 in the hundredth place tells us to round the 6 in the tenth place up to a 7.
[tex]344.7 \ g \ Ti[/tex]
There are approximately 344.7 grams of titanium in 7.2 moles of titanium.
Predict whether solutions of each of the following salts will be acidic, basic, or neutral. Explain your reasoning for each by writing a balanced net ionic equation to describe the chemistry of each non-neutral salt in water:
a. NaCN
b. KNO3
c. NH4Cl
d. NaHCO3
e. Na3PO4.
Answer:
NaCN- basic salt
KNO3 - neutral salt
NH4Cl - acid salt
NaHCO3 - acid salt
Na3PO4 - acid salt
Explanation:
Salt hydrolysis a process by which salts react with water giving an acid and a base.
When we dissolve NaCN in water, we have;
NaCN + - ⇄ Na^+ + CN^-
KNO3 ------> K^+ + NO3^-
NH4Cl ------> NH4^+ + Cl^-
NaHCO3 -----> Na^+ + HCO3^-
Na3PO4 ----> 3Na^+ + PO4^3-
Note that if a salt is formed from a weak acid and a strong base, the salt will be a basic salt e.g NaCN formed from weak HCN and strong NaOH.
If a salt is formed from a strong acid and weak base, the salt will be acidic, e.gNH4Cl formed from weak NH3 and strong HCl.
If a salt is formed from a strong acid and strong base, the salt will be neutral, e.g KNO3 formed from strong KOH and strong HNO3.
Name the following compound: CH3CH2CH2CH2CH2CH2CCCH3
2-nonene
7-nonyne
2-heptyne
2-nonyne
Finding Nemo??? sorry I really need these points
Answer:
2-nonyne
explanation:
First consider the type of bonds, there are tripple bonds of carbon to carbon, in position 2 from the right.
hence it us alkyn.
There are 9 carbons.
do you think that religion and science are in conflict ,or that people can both have both without any problems
What is the volume of the fluid in the graduated cylinder measured to the correct degree of precision?
37.22 mL
38.05 mL
37.0 ml
37.8 ml
Answer:
37.0. gsgggsgsghddhhdd
17. According to Newton's first law, an object in motion will stay in what kind of
motion as long as the net forces acting on it are zero?
A. slowing motion in a straight line
B. accelerating motion in a straight line
C. constant motion in a straight line
D. constant motion in an unpredictable direction
Answer:
C
Explanation:
According to Newton's first law, an object in motion will stay in motion unless acted upon by an unbalanced force. The option which gives the same meaning is :
constant motion in a straight lineAccording to Newton's first law, an object in motion as long as the net forces acting on it are zero will stay in:
C. constant motion in a straight line
A constant motion in mechanics is a number that remains constant throughout the motion, effectively placing a restriction on the motion.
What is Newton's first law of motion?The foundation of classical mechanics is made up of the three laws of motion that Newton suggested. These three physical laws. In accordance with the three laws of motion, a body's connection to the forces operating on it and the motion that resulted from those forces are both described. As Galileo's law of inertia, Newton's First Law of Motion is also referred to. If a body is not forced by an outside force to change its condition, it will remain in its state of rest or uniform motion in a straight line. As a factor that has the potential to alter an object's condition, the law defines force and mentions it.In this way, Newton uses the inertia of rest, motion, and direction to describe his first law of motion.A body has an attribute called inertia that makes it resist changes to its state. A body's inertia of translational motion is measured by its mass.To learn more about Newton's first law of motion, refer to:
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Which of the following is an example of a scientific theory?
Matter can be neither created nor destroyed.
Force equals mass times acceleration.
Matter behaves the way it does because it is made of atoms.
There is probably life on Mars.
C. Matter behaves the way it does because it is made of atoms.
Answer:
Matter can neither be created nor destroyed
Explanation:
Mark me. as brainliest
1) What happens to the Mercury on a cool day in a thermometer??
Answer:
it's level goes down
Explanation:
because the temperature is low, so mercury level is down
In water, a substance that ionizes completely in solution is called a
Answer:
please mark me brainliest
Explanation:
In water, a substance that ionizes completely in solution is called a weak electrolyte.
Answer: strong electrolyte.
Explanation: In water, a substance that ionizes completely in solution is called a. a. weak electrolyte.
When a chemical changes from the solid phase to the gas phase, this is an example of What chemical property?
Answer:
sublimation
Explanation:
solid => liquid Melting
liquid => solid freezing
liquid => gas evaporation
gas => liquid condensation
solid => gas sublimation
gas => solid deposition (e.g.; formation of frost), however some scholars will also refer to this process as sublimation.
pls help!!! How can you prove the pennies are made of different material aside from cutting them in half?
Answer:
Most of our coins are metal sandwiches. The outside layers are three-quarters copper and one-quarter nickel, and the "filling" is solid copper. Pennies are made of zinc coated with copper. Only nickels are one solid material—that same 75% copper/25% nickel alloy
Explanation:
What is Entropy?
A. The opposite of Enthalpy
B. The temperature at which a reaction is feasible.
C. A measure of disorder.
D. Free energy used for a reaction.
Answer:
C. A measure of disorder :)
Compared to an atom of C-12, an atom of C-14 has
A) fewer protons
C) more neutrons
B) fewer neutrons
D) more protons
Explanation:
Carbon-12 atoms have stable nuclei because of the 1:1 ratio of protons and neutrons.
Carbon-14 atoms have nuclei which are unstable. C-14 atoms will undergo alpha decay and produce atoms of N-14. Carbon-14 dating can be used to determine the age of artifacts which are not more than 50,000 years old.
Rewrite this measurement with a simpler unit, if possible.
4.5·m2m2m
Answer:
why are people s opinions and prejudices her greatest obstacles
Explain why it is not advisable to add water to acid when
mixing them
Answer:
Consequence
you form an extremely concentrated solution of acid initially.and the solution may boil very violently, splashing concentrated acid. I hope this helped! :)Balance the following reaction:
_______ CO₂ + _______ H₂O + heat ↔ _______ C₆H₁₂O₆ + _______ O₂
Please explain!
*Note: If any of the coefficients are the number one. Please, write "1" in the space. Thanks!
Answer:
6CO2+6H2O+heat" C6H12O6+6O2
the best way to balance a chemical reaction is to start with balancing the hydrogen followed by the other elements then lastly oxygen.so in this case if you put a 6 in front of carbon dioxide,water and oxygen you will definitely balance it.cause at the first side you have 6 carbons similar to the product,12 oxygen similar to the product and 18 oxygen similar to the products.
I hope this helps
Answer:
Explanation:
I saw this after answering your other question on the same reaction.
To balance the chemical reaction, look at the reactants and products. As O is part of both products, focus on C and H instead.
On the products side, 1 C6H12O6 has 6 C and 12 H. So that requires the same numbers of C and H on the reactant side because of mass conservation.
That gives 6 CO2 and 6 H2O as the reactants. Counting the number of O in the reactants, there are 6*2 + 6 = 18 O. Subtracting the 6 O in C6H12O6, that leaves 12 O so there are 12/2 = 6 O2 in the products.
Combining the numbers above, the balanced equation is:
___6___ CO₂ + ___6___ H₂O + heat ↔ ___1___ C₆H₁₂O₆ + ___6___ O₂
Which of the following stays constant when diluting a solution?
Select the correct answer below:
A) volume
B) molarity
C) concentration
D) amount of solute
Answer:
when you're diluting a solution, you're adding in more solvent, so the solute will maintain the same (D)
A student has accidentally spilled 100.0 mL of 3.0 mol/L nitric acid onto the lab bench. What mass of sodium bicarbonate would the teacher need to sprinkle on this spill to neutralize and clean it up?
Answer:
25 g
Explanation:
Step 1: Write the balanced equation
HNO₃ + NaHCO₃ ⇒ NaNO₃ + H₂O + CO₂
Step 2: Calculate the reacting moles of HNO₃
100.0 mL of 3.0 mol/L HNO₃ reacted.
0.1000 L × 3.0 mol/L = 0.30 mol
Step 3: Calculate the reacting moles of NaHCO₃
The molar ratio of HNO₃ to NaHCO₃ is 1:1. The reacting moles of NaHCO₃ are 1/1 × 0.30 mol = 0.30 mol.
Step 4: Calculate the mass corresponding to 0.30 moles of NaHCO₃
The molar mass of NaHCO₃ is 84.01 g/mol.
0.30 mol × 84.01 g/mol = 25 g
How do the particles in plasmas compare with
the particles in solids?
O Plasmas and solids are both made up of cation-anion pairs.
• Solids and plasmas are both made up of electrons and cations.
Solids are made up of cation-anion pairs, but plasmas are not.
O Plasmas are made up of cation-anion pairs, but solids are not.
Answer:
Solids are made up of cation-anion pairs, but plasmas are not
Explanation:
Solid is made from cautions and anions while the plasma is not and hence both are made from the cautions and anion plasma. Solids and plasma is made from electrons and solids are made from caution and anion pairs. Plasma is a good conductor of electricity as they have a lot of mobile charged particles.5.32 picometers is the same as
A.5.32 x 10^-12 meters
B.5.32 x 10^12 meters
C.5.32 x 10^9 meters
D.5.32 x 10^2 meters
At constant temperature and pressure, if 0.4 mole of a gas. A occupies 220 ml, and x mole of B gas occupies 120 ml. what is the number of moles of gas B?
Answer:
0.218mol
Explanation:
Using Avogadro's law equation;
Va/na = Vb/nb
Where;
Va = volume of gas A
Vb = volume of gas B
na = number of moles of gas A
nb = number of moles of gas B
According to the information in this question,
na = 0.4mol
nb = x mol
Va = 220ml
Vb = 120ml
Using Va/na = Vb/nb
220/0.4 = 120/x
Cross multiply
0.4 × 120 = 220 × x
48 = 220x
x = 48/220
x = 0.218mol
