Answer:
Burning of fossil fuels
Explanation:
Human activities that increase the amount of carbon dioxide in the atmosphere are;
1) Burning of fossil fuels in industrial and internal combustion engines
2) Depletion of the available forest cover, due to the consumption of wood as a raw material
3) Farming expansion that lead to clearing of forests for farming
4) Industrial activities such as the production of cement
5) Deforestation to provide land for development including buildings and infrastructure.
Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0012 % Pb by mass. What volume of the water in milliliters contains 100 mg of Pb
Answer:
8.3 × 10³ mL
Explanation:
Step 1: Calculate the mass of water that contains 100 mg of Pb
The concentration of Pb in the sample is 0.0012% by mass, that is, there are 0.0012 g of Pb every 100 g of water. The mass of water that contains 100 mg (0.100 g) of Pb is:
0.100 g Pb × 100 g Water/0.0012 g Pb = 8.3 × 10³ g Water
Step 2: Calculate the volume corresponding to 8.3 × 10³ g of water
Since the solution is diluted, we will assume the density of the sample is equal than the density of water (1 g/mL).
8.3 × 10³ g × 1 mL/1 g = 8.3 × 10³ mL
The volume of the water in milliliters contains 100 mg of Pb is;
V = 8.3 × 10³ mL
Volume of SolutionWe are given the concentration of Pb in the sample as 0.0012% by mass.
That means that there are 0.0012 g of Pb in every 100 g of water.
Thus, the mass of water that contains 100 mg (0.100 g) of Pb is calculated as;
(0.100 g Pb × 100 g of Water)/0.0012 g of Pb = 8.3 × 10³ g of Water
Now, we know that the density of water (1 g/mL) but we are not given the density of the sample.
Thus, since the solution is diluted we can equally say that;
Density of sample = 1 g/mL
Formula for Volume is;
V = mass/density
Thus;
V = 8.3 × 10³ g/1 g/mL
V = 8.3 × 10³ mL
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A toy plane has a mass of 2.5kg and is 18 m above the ground. It is moving 4.5 m/s.
how much mechanical energy does the toy have?
A. 416J
B. 441J
C. 466J
D. 491J
Answer:
466J (c)
Explanation:
Mechanical Energy= Kinetic+Potential
Potential energy= mgh
Plug in givens
mgh=2.5*18*9.8=441J
Kinetic Energy = 1/2mv^2
Plug in givens
1/2mv^2= 1/2(2.5)(4.5)^2= 25.3125J
Mechanical energy= 441J+25.3125J=466.3125J or 466J
he ______ is the depth in the ocean at which calcareous skeletal material first begins to dissolve. Multiple choice question.
Answer: lysocline
Explanation:
Lysocline is the depth in the ocean at which calcareous skeletal material first begins to dissolve. It is the depth of the ocean whereby the dissolution rate of calcite has a dramatic rise.
Lysocline is also referred to as the transition zone upper bound where the CaCO3 content drops.
balance the following half equation. SO3^2- ➡️SO4^2-
Answer:
[tex]12H2O + 2(SO3)2 -> 3(SO4)2[/tex]
Explanation:
see below. This was balanced using the the aggregate redox species method, or ARS for short.
The balanced half equation of the given reaction can be written as:
[tex]SO_3^{2-} + H_2O \longrightarrow SO_4^{2-} +2H^+ +2e^-[/tex]
What is the balanced chemical equation?A chemical equation can be defined as the expression of a reaction in terms of chemical symbols of the elements. A chemical equation of the reaction involves reactants and formed products.
The chemical equation of the reaction in which the number of atoms of the elements is the same on both sides of the chemical equation is a balanced chemical equation.
According to the law of conservation of mass, the total mass of the elements on the reactant side and product side should be the same in a balanced equation.
Given the equation is SO₃²⁻ → SO₄²⁻
To balance the oxygen on both sides add water:
H₂O + SO₃²⁻ → SO₄²⁻
To balance the hydrogen on both sides add H⁺:
H₂O + SO₃²⁻ → SO₄²⁻ + 2H⁺
To balance the charges, add electrons:
H₂O + SO₃²⁻ → SO₄²⁻ + 2H⁺ + 2e⁻
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A typical scuba tank has a volume of 11 liters and can support a diver for one hour. An adult breathes about 3 liters of air with each breath.
How can an 11-liter tank give a diver enough oxygen for one hour?
Answer:
The correct answer is - at high pressure a huge amount of gases can be stored in less volume.
Explanation:
We already know that pressure is inversely proportional to the volume of gas which means if we increase the pressure the volume of gas becomes less.
P = 1/V
So in the scuba divers tank, the oxygen is filled at very high pressure so the high amount of the oxygen can be filled in less volume and which will last for longer than a normal pressure tank can last.
what is the [h+] if the ph of a solution is 11.13
pls help
Explanation:
[tex][{H}^{ + }] = {10}^{ - pH} [/tex]
[tex] = {10}^{ - 11.13} [/tex]
[tex] = {10}^{ (- 11 - 0.13)} [/tex]
[tex] = {10}^{ - 0.13} \times {10}^{ - 11} [/tex]
[tex] = 0.741 \times {10}^{ - 11} \frac{mol}{litre} [/tex]
HOPE IT HELPS YOUCalculate the numerical Kc value for the following reaction if the equilibrium mixture contains 0.51 M CO , 0.30 M H2 , 1.8 M CH4 , and 2.0 M H2O.
CO(g) + 3H2 (g) ⇌ CH4 (g) + H2O (g)
Show work
Answer:
uh i think this is the answer
Explanation:
PLEASE HELP ASAP!!!!!!!!
Answer:
ouch......it's kinda a practical question..
Answer: ?
Explanation: what was the answer?
Question 3 of 10 What does the first ionization energy represent? O A. The energy required to add an electron to a new energy level B. The energy to remove an energy level of electrons O C. The energy given off when an electron is gained D. The energy required to remove an electron from an atom SUBMIT
Answer:
D
Explanation:
The first ionization energy is the minimum energy required to remove the most loosely bound electron from an atom.
Good luck!
describe the formation of ionic bonds in potassium chloride compound (5 marks)
Answer:
When the two atoms are in contact, potassium readily transfers its outer electron to chlorine which readily accepts it, resulting in both atoms achieving a state of eight outermost electrons. With this electron transfer, the ionic bond in KCl is formed.
The most common carrier of communicable diseases are
a.cockroach
b.housefly
c.mosquito
d.spider
housefly
Explanation:
Because it one of the affective vector of disease carrier and it always roam towards wastes and dirty materials likely to get attracted . And it carries contagious disease from hospitals , infected patients , etc .
1. A) Calculate DO of water at 25 0 C, P 0 = 1.01x10 5 Pa; given: water vapor pressure (25 0 C) is 3.2x10 3 Pa and Henry constant of oxygen in water is 1.3x10 -8 mol/l.Pa b) How's DO content changed as increase or decrease water temperature? Explain.
Answer:
cfvgbhnjmk,
Explanation:
In an electrically neutral atom, the number of
protons equals the number of neutrons.
protons equals the number of electrons.
neutrons equals the number of electrons.
A. Protons equals the number of neutrons
B. Protons equal the number of electrons
C. Neutrons equals the number of electrons
Answer: B
Answer:
B
Explanation:
because protons have a +1 charge and electrons have a -1 charge, so if an atom is neutral it must have the same amount of protons and neutrons
Select the correct answer.
0.22 M
HCI
Unknown
LiOH
What is the concentration of the base (LIOH) in this titration?
1.0 ml
0.5 ml
Initial
burette
reading
Final
burette
reading
13.3 ml
18.5 ml
OA
0.16 M
ОВ.
0.15 M
OC. 0.22 M
OD
18 M
O E
0.5 M
Daset
Answer:
=0.15M
Explanation:
To get the moles of the unknown LiOH, calculate the number of moles of HCl in 12.3mL.
Using the stoichiometric coefficient, mole ratio 1:1.
This means that the number of moles is the same. This number of moles is contained in 18mL. Then Calculate the molarity (concentration) which is in 1000mL
See the explanation from the image I have shared with you for calculations.
2002040_MIJ COMP SCI 1_SEM 1 CR_PY
The three main types of scientific investigations are descriptive, comparative, and experimental. Which components
are included in all three types of investigations?
a scientific question
an independent variable
a dependent variable
a procedure
a control group
a conclusion
Answer:
a scientific question
Procedure
Conclusion.
Explanation:
Scientific investigation is usually carried out to explain and give answers to natural phenomenon. Now, this scientific investigation is performed through the three main types as described in the question.
With that being said, the most common parts of all types of investigation are :
1. Scientific question: In this stage, questions are usually asked on the basis of observation made which could be answered.
2. Procedure: In this stage, the dimension of the steps are followed to answer and test the scientific question.
3. Conclusion: This is the primary aim that we check when done with our sample values
different oil refineries in UAE
Answer:
Petroleum refinery capacity in the UAE 2009-2018
In 2018, the total production capacities of all refineries in the UAE were 1.13 metric barrels per day. Total total production capacity of the al-Ruwais refinery in the United Arab Emirates was approximately 817,000 metric barrels per day.
Someone please do a True or false of all of these
Answer:
1. False
2. True
3. False
4. False
5. True
6. False
7. True
8. True
9. True
3. If there were multiple products comment on finding the mixture melting point of the products. Does your sample appear to be a mixture or pure
Answer:
If there were multiple products, we can take each product and mixed with a sample of a pure compound that we suspect might be the same as the product. Then, we taking the melting point of this mixture that contains one of our product and pure sample. Then, we can observe the change in melting point, if there is no change in melting point or the melting stays in the same range of the pure compound. Then, the that product along with the pure sample are actually the same compound, not a mixture of two compounds. However, if the melting point for our pure sample compound changed or didn't stay in the same range after the mixing with on of our products. then we can conclude that this product and the pure sample are completely different compound, and indeed they are a mixture.
explain with example the need of standard measurement system
Answer:
A standard system of measurement is very important because it helps us from making mistakes at the moment of doing calculations and correctly working...
Answer:
A standard measurement system is important because it allows scientists to compare data and communicate with each other about their results. Metric System – is a measurement system based on the number 10.
Which statement is the best description of a chemical bond
Answer:
What are your given options? I can't answer unless I know those :)
Explanation:
please help. need this asap!!
Answer:
E.....Na2I.,.
Explanation:
Cuz sodium has a Vallency..1......lodide has Vallency 2
You are a chemist working in your laboratory. In your storage closet you have a
cabinet that holds only samples of pure elements, no compounds. While looking for a
sample of lithium (LI), you notice that the label on one bottle has worn off. The room is
at normal temperature. The contents of the bottle are liquid and do not look metallic.
What element should you relabel the bottle as?
A.Helium
B.Bromine
C.Arsenic
D.Chlorine
Crystals of sodium chloride were prepared by the following method.
1 25.0 cm3
of dilute hydrochloric acid was accurately measured into a conical flask.
2 Aqueous sodium hydroxide was added until the solution was neutral. The volume of
sodium hydroxide added was measured.
3 The solution was evaporated and the crystals washed with approximately 15 cm3
of water.
Which row shows the pieces of apparatus used to measure the 25.0 cm3
of hydrochloric acid, the
volume of aqueous sodium hydroxide and the 15 cm3
of water?
Answer: the answer is C
IF U MIGHT NEED AN EXPLANATION FEEL FREE TO COMMENT
The laboratory equipment like the burette, pipette, and measuring cylinders are used in process of titration process. The solution of NaOH is added by the burette. Thus, option C is correct.
What is titration?Titration has been the analytical technique that uses the known and measured quantity of the solution to estimate the volume of another solution with an unknown volume and known molar concentration.
The laboratory equipment like burette, pipette, and measuring cylinders are used in measuring the volume in the titration process. The burette is filled with sodium hydroxide to measure its quantity.
The pipette is used to transfer the volume of the solution that is known (hydrochloric acid) and the measuring cylinder is used to measure the liquid (water) that is used in chemistry experiments.
Therefore, option C. pipette, burette, and measuring cylinder are the apparatus used in the titration process.
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Balancing equations
1. __Na + __Oz -> __Na2O
Answer:
Balancing equations
1
[tex]4Na + O_{2} -> 2Na_{2}O[/tex]
A 15.8 g sample contains 3.60 g F, 4.90 g H, and 7.30 g C. What is the percent composition of hydrogen in this sample?
Answer: 22.7848% F or 23%
Explanation: %F = 3.6g/15.8g • 100% = 22.7848% F
The percentage composition of hydrogen in the given sample is equal to 31%.
What is percentage composition?The percentage composition of a given compound can be described as the ratio of the quantity of each element to the total quantity of individual elements in the compound multiplied by 100. The quantity can be measured in terms of grams of the elements present in the sample.
The percent composition is expressed in its composition in terms of all the elements present. Thus, it helps in the chemical analysis of any given compound.
The percentage composition is expressed using the following formula,
Percentage composition of E = (E/T) × 100
Where E represents the total quantity of element E present in the compound and T represents the total quantity of all the elements present in the compound.
Given, the mass of the F, H, and C is 3.60g, 4,90 g, and 7.30 g respectively.
The total mass of the given sample = 15.8 g
The mass of the hydrogen in the sample = 4.90 g
The percent composition of H = (4.90/15.8) × 100 = 31 %
Therefore, the percent composition of hydrogen in this sample is 31%.
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What is the general function of enzymes in the human body?
O A. They make fatty acids unsaturated.
OB. They speed up chemical reactions.
O C. They store genetic information.
D. They carry instructions for making proteins.
Answer:
C
they store genetic information
B. They speed up chemical reactions
Metals like potassium and sodium are kept in paroffin oil. Why?
Answer:
because they are high reactive to the air thats why we keep them in paroffin oil
How many moles of water vapor are formed. when 10 litres of butane gas c4h10 is burned in oxygen at STP
Using the idea of the molar volume of butane gas, we have 2.23 moles of water vapor.
What is a reaction equation?The term reaction equation shows the conversion of reactants to products. First of all, we must get down the reaction equation as follows;
C4H10(g) + 13/2O2(g) ----> 4CO2 (g) + 5H2O(g)
From the balanced reaction equation;
1 mole of butane gas yields 5 moles of water vapor. Since 1 mole of butane gas occupies 22.4 L. Hence;
22.4 L of butane yields 5 moles of water vapor
10 L of butane gas yields 10 L * 5 moles/22.4 L = 2.23 moles
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1 x 10^-3 m is the same as which of the following? Select all that apply.
a
10000 m
b
1/1000 m
c
1/0.1 m
d
0.001 m
e
100 m
Answer: b and d
Explanation:
1×10^-3=1×1/10³=1×1/1000=1/1000 so b is correct
1×10^-3=1/1000=0.001
so d is correct
why is the reaction of Iron and hydrochloric acid slow
Answer:
The chloride formed when iron reacts with hydrochloric acid is iron (II) chloride, also known as iron dichloride. The reaction between iron and hydrochloric acid is slower than the reaction with zinc, with much smaller hydrogen bubbles produced.
Answer:
The reaction of iron and hydrochloric acid is slow beacause When dilute Hydrochloric acid is added to iron filings, iron(II) chloride & hydrogen gas is produced. In this reaction iron displaces hydrogen from hydrochloric acid to form iron chloride & hydrogen gas this reaction is a single displacement reaction which reacts slowly.
Explanation:
