Answer:
D
Explanation:
Scientists will use a scientific notation because, it provides the easier way to write a very large and very small numbers. Option D is correct.
Scientists use scientific notation to express numbers that are extremely large or small. Scientific notation allows for a more concise representation of these numbers by expressing them as a product of a coefficient and a power of 10.
For very large numbers, scientific notation makes it easier to handle and compare values. It allows scientists to focus on the significant digits and the scale of the number without having to write out all the zeros. It also simplifies calculations and reduces the chance of errors when dealing with such large values.
Similarly, for very small numbers, scientific notation provides a convenient way to express values without writing out a large number of decimal places. It allows scientists to express the magnitude of the number in a concise manner and enables easier comparison and calculations with other values.
Scientific notation is widely used in scientific fields such as physics, chemistry, astronomy, and engineering, where dealing with numbers of varying magnitudes is common. It provides a standardized and efficient way to represent and work with very large and very small numbers.
Hence, D. is the correct option.
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When a chemical reaction occurs,____.
Answer:
when chemical bonds between atoms are formed or broken
What is the mass of 0.251 moles of water? Using dimensional analysis show work
[tex]1 \text{ mol of H}_2 \text{O} \equiv 18 \text{ g} \implies 0.251 \text{ moles of H}_2 \text{O} \equiv 4.518 \text{ g}[/tex]
Because of heredity, members of the same species do not have the same traits.
True or false
Answer:
false
Explanation:
use the rapid quark for a explain
In lab, you calculate the density of an iron rod to be 7.30 g/cm3. The accepted value
for the density of iron is 7.80 g/cm3. What is your percent error?
Answer:
6.41 %Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]
From the question
actual density = 7.80 g/cm³
error = 7.30 - 7.80 = 0.5
We have
[tex]p(\%) = \frac{0.5}{7.8} \times 100 \\ = 6.410256...[/tex]
We have the final answer as
6.41 %Hope this helps you
. If you have 5.42 x 1024 aluminum atoms, approximately how many moles is that?
Please help me
Answer:
5.42x10^24 atoms/1 x 1 mole/6.022x10^23
= 9.5 mol
Aluminum reacts with oxygen to form aluminum oxide. Select the correct unbalanced skeleton equation for this reaction. A. Al(s) + 0(g) - AIO(s) B. Al203(s) - Al(s) + 02(8) C. Al(s) - 02(8) + Al203(s) D. Al(s) + 02(8) - Al203(s)
Answer:
D. Al(s) + O₂(g) → Al₂O₃(s)
Explanation:
Aluminum is a solid metal, so it is written as Al(s).
Oxygen is a diatomic gas, so we write this compound as O₂(g).
Aluminum oxide has the formula Al₂O₃ because in oxides the oxidation number of oxygen atom is -2 and for aluminum, the oxidation number is 3. Thus, we write this compound as Al₂O₃(s).
Now, we have to found the chemical equation in which the reactants (left side) are Al(s) and O₂(g) while the product (right side) is Al₂O₃(s). From the options, we can see that the correct is (D):
Al(s) + O₂(g) → Al₂O₃(s)
What makes up a compound
Answer:
Elements make up a compound.
Please help! I don't know how to do and want to understand
Which of these takes place when a chemical change occurs? option 1: Bonds connecting atoms in products and reactants form. option 2: Bonds connecting atoms in products and reactants break. option 3: Bonds connecting atoms in reactants break, and bonds connecting atoms in products form. option 4: Bonds connecting atoms in reactants form, and bonds connecting atoms in products break.
Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
Explanation:
A change that leads to the change in chemical composition of a substance is called a chemical change.
For example, [tex]2NH_{3} \rightarrow N_{2} + 3H_{2}[/tex]
Here, bond between the reactant atoms nitrogen and hydrogen is broken down.
On the other hand, bond connecting the products that is [tex]N_{2}[/tex] and [tex]H_{2}[/tex] is formed.
Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
The atoms of which element bond to one another in chains, rings, and networks?
1.
barium
2.
carbon
3.
iodine
4.
mercury
Submit An:
Why increasing the temperature of a gas would increase the volume of its container in gas law?
When the amount of gas in a container is increased, the volume increases. Lussac's law states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.
help bc i need it lol
Answer:
2 XE + 1 AB. --> 1 AE2 + 2 XB
Above equation is now balanced
How long is radioactive waste from nuclear plants radioactive?
1.) 100,000 years
2.) 10,000 years
3.) 100 years
4.) 1,000 years
In its aqueous solution, 32% of a substance dissociates to release hydroxide ions. Which of the following is true for the substance? (3 points)
It is a weak acid
It is a weak base.
It is a strong acid
It is a strong base.
*please only answer is you have the real answer bc I really need to bring up my grade*
Answer:
It is a weak base.
Explanation:
A base is a substance that releases hydroxide ion (OH-) when in an aqueous solution, according to Svante Arrhenius definition of a base. However, a base is said to be either strong or weak depending on it is able to dissociate.
A weak base is a base that does not completely dissociate into hydroxide ions in an aqueous solution while a strong base dissociates completely. According to this question, 32% of a basic substance ( because it can dissociate into OH-) dissociates to release hydroxide ions. This means that since it does not totally dissociate i.e. 100%, it is a WEAK BASE.
Answer:
It is a weak base.
Explanation:
Guy above me is right and I took the test :)
Which electron in an atom (Z=17) is the most shielded from
nuclear charge?
A. an electron in the 2s
B. an electron in the 3p
C. an electron in the 3d
D. an electron in the 1s
Answer:
option no. C is correct
an electron in the 3d
Number of molecules in 16 grams of h2co3
For this one u can work out the amount of moles in h2co3 by using moles=mass/mr(of h2co3 is 52)
so 16/62=0.258moles then u use the equation
number of particle = moles × 6.02×10^23
=0.258×6.02 ×10^23
=1.55×10^23 molecules.
hope this helps
The skin has and needs natural oils. Why is it advisable
to wear gloves while working with strong alkalis ?
Answer:
As we know that alkalis react with oil to form soap. As our skin contains oil so when we touch strong alkalis, a reaction takes place and the soapy solution is formed. Hence we should wear gloves.
Answer:
As we know that alkalis react with oil to form soap. As our skin contains oil so when we touch strong alkalis, a reaction takes place and the soapy solution is formed. Hence we should wear gloves.
Explanation:
it from internet
If I threw a block of sodium into a lake, and the H2 created took up 34 L of space at STP (standard temperature and pressure: 1 atm and 0C), how many grams of Na did I begin with?
Answer:
70g Na
Explanation:
The sodium reacts with water as follows:
2Na + 2H2O → 2NaOH + H2
Where 2 moles of Na produce 1 mole of H2.
To solve this question we must find the moles of H2. With the balanced equation we can find the moles of Na and its mass as follows:
Moles H2:
PV = nRT; n = PV/RT
Where P is pressure = 1atm,
V is volume = 34L,
R is gas constant = 0.082atmL/molK
T is absolute temperature = 273.15K = 0°C
Replacing:
n = 1atm*34L/0.082atmL/molK*273.15K
n = 1.52 moles H2
Moles Na:
1.52 moles H2 * (2mol Na / 1mol H2) = 3.04 moles Na
Mass Na-Molar mass: 22.99g/mol-
3.04 moles Na * (22.99g / mol) =
70g Na
When naming a molecule, how do you indicate that the carbons on either side
of the double bond are pointing in opposite directions?
Answer:
use the prefix trans-
When naming a molecule, we indicate that the carbons on either side of the double bond are pointing in opposite directions by adding a prefix (-trans) in the name of the molecule.
What is IUPAC nomenclature?IUPAC nomenclature of organic compounds refers to the systematic approach taken for the nomenclature of organic compounds as per the recommendation of the International Union of Pure and Applied Chemistry.
If alkenes have two different substituents at each end of the C=C then they can exist as stereoisomers (as geometric isomers).
This is because there is restricted rotation of the double bond due to the pi bond which means they don't readily interconvert.
cis- if the two alkyl groups, R-, are on the same side of the C=Ctrans- if the two alkyl groups, R-, are on opposite sides of the C=C.Therefore, When naming a molecule, we indicate that the carbons on either side of the double bond are pointing in opposite directions by adding a prefix (-trans) in the name of the molecule.
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In the titration of a solution of Sodium hydroxide, an acid titrant was prepared by diluting 125.0 mL of 10.00 mol/L Nitric acid into enough distilled water to make 500.0 mL of solution. 30.0 mL of the base was measured, and in the titration, 16.74 mL of the acid titrant was needed to neutralize. Determine the concentration of the Sodium hydroxide.
Answer:
1.395M NaOH
Explanation:
Sodium hydroxide, NaOH, reacts with nitric acid, HNO3, as follows:
NaOH + HNO3 → NaNO3 + H2O
Where 1mol of NaOH reacts with 1mol of HNO3
To solve this question we must find the concentration of the titrant. With the concentration and the needed acid we can find the moles of HNO3 added = moles NaOH in the solution. With the moles of NaOH and its volume we can find its concentration as follows:
HNO3 concentration:
10.00mol/L HNO3 * (125.0mL/500.0mL) = 2.500M HNO3
Moles HNO3 = Moles NaOH:
16.74mL = 0.01674L*(2.500mol/L) = 0.04185 moles HNO3 = Moles NaOH
Concentration NaOH:
0.04185 moles / 0.0300L =
1.395M NaOH
The molar mass of copper(II) chloride (CuCl2) is 134.45 g/mol. How many formula units of CuCl2 are present in 17.6 g of CuCl2?
Answer:
7
Explanation:
took test
Will give brainliest
Process name of water vapor to ice
Answer:
Deposition
this is the process of a substance changing its state from gas to solid. Solid to gas is known as sublimation
125 cm3 of a solution contains 0.25 moles of the solute. What is the concentration of the solution?
Answer:
Explanation:
125 cm3 -> 0.125 L
M = no. mole / volume (L)
M = 0.25 / 0.125 = 2 M
Which of these is an example of a prosthesis?
A. A hearing aid
B. A textbook
C. Gloves
D. A pair of boots
Answer:
hearing aid
Explanation:
an artificial body part
A hearing aid is an example of a prosthesis. Therefore, option A is correct.
A prosthesis is an artificial device or replacement for a missing body part or function. In the case of a hearing aid, it is a device designed to assist people with hearing loss by amplifying sound. It acts as a substitute for the natural function of the ear.
A textbook is a written educational resource, gloves are protective coverings for the hands, and a pair of boots is footwear. These items do not serve as artificial replacements for missing body parts or functions.
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This woman comes to the clinic with high blood pressure,
hyperglycemia(high blood sugar), weakening of the bones and severe
depression of the immune system. Can you diagnose her condition?
Is soup pure or impure?
Answer:
I think it's impure . Hope this helps you
Answer:
I think is pure but not 100% pure.
The diagram shows the basis for forming which of the following?
O nucleic acids
O proteins
O polysaccharides
O lipids
Please help .. I’m really stuck
Answer:
See explanation
Explanation:
pOH = -log[OH^-]
pOH =-log[1×10^-4 molL-1]
pOH = 4
pH +pOH =14
pH = 14 -4
pH =11
b) pOH = -log[OH^-]
pOH =-log[4.9×10^-2molL-1]
pOH = 1.31
pH +pOH =14
pH = 14 -1.31
pH =12.69
c)
pH= -log[H^+]
[H^+] = Antilog [-pH]
[H^+] = Antilog [-3]
[H^+] = 1 × 10^-3 molL-1
d) pOH = -log[OH^-]
[OH^-] = Antilog[-pOH]
[OH^-] = Antilog[-10.4]
[OH^-] = 3.98 ×10^-11
[OH^-] [H^+] = 1 × 10^-14
[H^+] = 1 × 10^-14/3.98 ×10^-11
[H^+] =2.5 ×10^-4 MolL^-1
e) A solution of pH 9 is basic because the pH scale is calibrated in such as way that 0-6.9 is acidic, 7 is neutral and 8 - 14 is basic.
f)
[H^+] = number of moles/volume
[H^+] = 0.35 moles/8L
[H^+] = 0.044 MolL^-1
pH = - log [H^+]
pH = -log [0.044 MolL^-1]
pH= 1.36
249 g of potassium iodide, KI, is mixed with 496.5 g of lead(II) nitrate, Pb(NO3)2.
The equation of the reaction is represented below.
[Pb(NO3)2 = 331; KI = 166; PbI2 = 461, KNO3 = 101]
Calculate the number of moles of excess reagent left.
Give your answer to three significant figures.
Answer: The number of moles of excess reagent left is 0.750 moles
Explanation:
The number of moles is calculated by using the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For KI:Given mass of [tex]KI[/tex] = 249 g
Molar mass of [tex]KI[/tex] = 166 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of KI}=\frac{249g}{166g/mol}=1.5mol[/tex]
For [tex]Pb(NO_3)_2[/tex]:Given mass of [tex]Pb(NO_3)_2[/tex] = 496.5 g
Molar mass of [tex]Pb(NO_3)_2[/tex] = 331 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of }Pb(NO_3)_2=\frac{496.5g}{331g/mol}=1.5mol[/tex]
The given chemical equation follows:
[tex]2KI+Pb(NO_3)_2\rightarrow 2KNO_3+PbI_2[/tex]
By stoichiometry of the reaction:
If 2 moles of KI reacts with 1 mole of lead(II) nitrate
So, 1.5 moles of KI will react with = [tex]\frac{1}{2}\times 1.5=0.75mol[/tex] of lead(II) nitrate
As the given amount of lead(II) nitrate is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.
Thus, KI is considered a limiting reagent because it limits the formation of the product.
Moles of excess reactant ([tex]Pb(NO_3)_2[/tex]) left = [1.5 - 0.75] = 0.750 moles
Hence, the number of moles of excess reagent left is 0.750 moles
What type of experiment did the student in the passage perform?
Answer:
Passage?
Explanation:
