Answers
Answer:
A
Explanation:
B: not B. Opinions don't matter. Facts do.
C: its a consideration. It will limit the scope of the experiment. But it's not relevant to the investigation. Not C
D: You might want to contact some scientists to see what they think about your investigation, but randomly interviewing anyone and everyone is not the answer.
You want to do A for certain.
Related Questions
The equation shows the reaction of sulfuric acid with sodium hydroxide:
H2SO4 + 2NaOH --> NaSO4 + 2H2O
25 cm^3 of sulfuric acid of concentration 0.2 mol/dm^3 reacted with exactly 10 cm^3 of sodium hydroxide. Calculate:
a) the number of moles of sulfuric acid present
b) the number of moles of sodium hydroxide reacting
c) the concentration of the sodium hydroxide in mol/dm^3
Answers
Answer:
(a).
[tex]{ \sf{1000 \: {cm}^{3} \: contains \: 0.2 \: moles \: of \: acid}} \\ { \sf{25 \: {cm}^{3} \: contains \: ( \frac{25 \times 0.2}{1000} ) \: moles}} \\ \\ = { \sf{0.005 \: moles}}[/tex]
» 0.005 moles of sulphuric acid are present.
(b).
from the equation:
[ 1 mole of acid reacts with 2 moles of sodium hydroxide ]
[tex]{ \sf{1 \: mole \: of \: acid \: reacts \: with \: 2 \: moles \: of \: hydroxide}} \\ { \sf{0.005 \: moles \: of \: acid \: react \: with \: (0.005 \times 2) \: moles}} \\ { \sf{ = 0.01 \: moles}}[/tex]
» 0.01 moles of sodium hydroxide reacted.
(c).
[tex]{ \sf{10 \: {cm}^{3} \: contains \: 0.01 \: moles \: of \: hydroxide }} \\ { \sf{1000 \: {cm}^{ 3} \: contain \: ( \frac{1000 \times 0.01}{10} ) \: moles}} \\ \\ { \sf{ = 1 \: mol \: {l}^{ - 1} }}[/tex]
» concentration is 1 M
Yasir wants to determine if there is a relationship between room color and sleep. Based on his research, Yasir makes an educated guess that people fall asleep more quickly in a room painted blue than in a room painted yellow. He asks several people which color they like better—yellow or blue—and uses their responses to determine if his educated guess was correct.
What is missing from Yasir's scientific investigation?
A testable hypothesis that is based on research
An experiment that directly tests the hypothesis
Variables to be tested by an experiment
Research on the topic to see what others have learned
Answers
Answer: B. An experiment that directly tests the hypothesis
Explanation:
Yasir didn’t really test his experiment he only ask people for the opinion on which color they like so he forget to actually do the experiment therefore the answer is b.
Answer:
B. an experiment that directly tests the hypothesis
Explanation:
this was on my test i got it right
A brick has a mass of 100 G and a volume of 25CM3 what is the density of the brick
Answers
Answer:
[tex]\boxed {\boxed {\sf 4 \ g/cm^3}}[/tex]
Explanation:
We are asked to find the density of a brick. Density is a substance's mass per unit volume. The formula for calculating density is as follows.
[tex]\rho= \frac{m}{v}[/tex]
The mass of the brick is 100 grams and the volume is 25 cubic centimeters.
m= 100 g v= 25 cm³Substitute the values into the formula.
[tex]\rho= \frac{ 100 \ g}{25 \ cm^3}[/tex]
Divide.
[tex]\rho=4 \ g/cm^3[/tex]
The density of the brick is 4 grams per cubic centimeter.
What is your experience in stars??
Answers
Answer:
Experience in star is very nice
Explanation:
Because i love stars
what is the flame color of potassium
Answers
Answer:
The flame colour of potassium is Lilac
THANKS
Someone plz help me !!
Science
Or
Bias?
Answers
This scale is being used to measure flour. What is the
scale really measuring about
the flour?
A. the color of the flour
B. the volume of the flour
C. the weight of the flour
D. the temperature of the
flour
Answers
The only thing you can measure with a scale is the weight of an object, not the colour, not the temperature, neither the volume.
Volume = length x width x height.
Temperature is the quantity measured by a thermometer.
Colours are derived by the amount of energy present at each spectral wavelength.
Weight is commonly measured using one of two methods. A spring scale or hydraulic or pneumatic scale measures local weight, the local force of gravity on the object (strictly apparent weight force).
descoberto em 1996 por pesquisadores alemães o novo elemento químico de numero 112 poderá ser batizado de copernicium em homenagem ao cientista e astronomo Nicolau Copérnico segundo os cientistas o elemento é aproximadamente é 277 vezes mais pesado que o hidrogênio, o que torna o elemento mais pesado da tabela periódica ocupando a posição relativaa ao 7°periodo do grupo 12. A tabela periódica, uma das realizaações mais notáveis da quimica, foi desenvolivda exclusivamente a partir das propriedades fisícas e químmicas dos elementos e, por isso, o conhecimento da posição ocupada por um elemento químico permite que se façam algumas previsões quanto às suas propriedades.
considerando a localização dos átomos dos elementos químicos x, y e z na tabela periódica é incorreto afirmar que
x = 3° período do grupo 1 (I A)
y = 2° período do Grupo 14 (IV A)
z = 2° período do grupo 16 (VI A)
Answers
Answer:
Loading...
Explanation:
What makes an atom radioactive?
Answers
Answer:
The unstable nucleus of radioactive atoms emit radiation.
Explanation:
When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced and unstable, or radioactive.
(https://www.epa.gov/radtown/radtown-radioactive-atom-activity-4-atomic-stability)
Answer:
When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable. Whether radioactive elements can become stable and if so, how. The unstable nucleus of radioactive atoms emit radiation. ... This process is called radioactive decay.
Explanation:
Magnesium occurs naturally in only three isotopes. ^24 Mg has an isotopic mass of 23.9850 amu and an abundance of 78.99%. ^25 Mg has an isotopic mass of 24.9858 amu and an abundance of 10.00%. Find the mass number of the last isotope of magnesium.
Can someone please explain how to solve this? *done mine the notes*
Answers
Answer:
25,98 amu and 11.01% abundance
Explanation:
1. Find the missing abundance
100 - 78.99 - 10 = 11.01 %
2. Using each mass and abundance and the periodic table for the Mg amu
And let Isotope = Mg
23.9850(78.99%) + 24.9858(10%) + Mg(11.01%) = 24.305 (100%)
Solve for Mg
Mg = 25,98
In a piece of medal, what holds the atoms together?
Answers
Explanation:
Metallic bond, force that holds atoms together in a metallic substance
difference between atom and ion
plz plz answer
Answers
Answer:
Atoms are neutral; they contain the same
samenumber of protons as electrons. By
definition, an ion is an electrically charged
particle produced by either removing
produced by either removingelectrons from a neutral atom to give a
produced by either removingelectrons from a neutral atom to give apositive ion or adding electrons to a neutral atom to give a negative ion.
how does calcium atomic radius compare to magnesium (Mg) radius and patssiuks (K) redius?
Answers
Answer:
The radius of a calcium atom would be larger than that of a magnesium atom.
The radius of a calcium atom would be slightly smaller than that of a potassium atom.
Explanation:
Refer to a modern copy of the periodic table.
Calcium and magnesium are in the same column. They are in the same group (IUPAC group [tex]2[/tex].)
Hence, atoms of calcium and magnesium would have similar effective nuclear charges. In other words, the attraction between a calcium atom nucleus and its valence electrons would be similar to that of magnesium.
However, calcium is in the fourth row of the periodic table (fourth period) while magnesium is in the third (third period.) A calcium atom would thus have four main shells with electrons. In contrast, a magnesium atom would only have three such main shells.
Despite the similar effective nuclear charge (effective attraction on the outermost electrons,) the radius of a calcium atom would be larger than that of a magnesium atom because of the extra main electron shell.
On the other hand, calcium and potassium are in the same row (same period.) A calcium atom and a potassium atom would both include four electron-filled main shells.
However, with one additional proton per atom, the effective nuclear charge of calcium atoms would be greater than that of potassium atoms. Hence, when compared to potassium nuclei, the nucleus of a calcium atom would pull its electron shells closer to the center. The radius of a calcium atom would thus be smaller than that of a potassium atom.
In general, atomic radius would generally become larger when moving down a column in the periodic table. On the other hand, atomic radius would general become smaller when moving towards the right-hand side of a row in the periodic table.
Helppppp……. Is this correct?
Answers
No.
The smallest quantity is 600 centiliter and the largest is 600 kiloliter.
What is the density of xylene (in g/mL) to two significant figures at 25°C?
Answers
Answer:
865 kg/m³; 0865 g/cm³
Explanation:
For the following pairs of ions, use the concept that a chemical compound must have a net charge of zero to predict the formula of the simplest compound that the ions are most likely to form. Write the formula of the metal first and follow by the non metal
Answers
[tex]\\ \sf\longmapsto FeP[/tex]
[tex]\\ \sf\longmapsto Fe_2S_3[/tex]
[tex]\\ \sf\longmapsto FeCl_2[/tex]
[tex]\\ \sf\longmapsto MgCl_2[/tex]
[tex]\\ \sf\longmapsto MgO[/tex]
[tex]\\ \sf\longmapsto Mg_3N_2[/tex]
[tex]\\ \sf\longmapsto Na_3P[/tex]
[tex]\\ \sf\longmapsto Na_2S[/tex]
[tex]\\ \sf\longmapsto CoO[/tex]
[tex]\\ \sf\longmapsto Co_2S_3[/tex]
[tex]\\ \sf\longmapsto AlCl_3[/tex]
[tex]\\ \sf\longmapsto CsBr[/tex]
[tex]\\ \sf\longmapsto Ti_2O_4[/tex]
[tex]\\ \sf\longmapsto Ag_2S[/tex]
Calculate the empirical formula of a compound that has a composition of 5.9% (by mass) hydrogen and 94.1% (by mass) oxygen.
Answers
Answer:
[tex]oxygen \: at \: 94.1\% \: hydrogen \: at \: 5.9\% \\ at \: 100gram \: oxygen \: \\ \: 94.1\% = .941 \times 100g \\ = 94.1 \times \frac{1mol}{16g} = 5.88g \\ hydrogen \: \\ 5.9\% = .059 \times 100 = 5.9 \times \frac{1mol}{1.002g} = 5.88g \\ here \: oxygen = hydrogen \: so \: ratio \\ = 1 \: \: \: 1 \: \\ emperical \: formula \: = oh\\ thank \: you[/tex]
Composition:
5.9% Hydrogen and 94.1% Oxygen (by mass)
in a 100 gram sample:
5.9 gram Hydrogen
94.1 gram Oxygen
Finding the number of moles:
Moles of Hydrogen:
moles = given mass/ molar mass
moles = 5.9 / 1 [molar mass of Hydrogen = 1g/mol]
moles of hydrogen = 5.9 moles
Moles of Oxygen:
number of moles = given mass / molar mass
number of moles = 94.1 / 16 [molar mass of Oxygen = 16g/mol]
moles of Oxygen = 5.88 ≈ 5.9 moles
Empirical Formula:
Moles of Hydrogen : Moles of Oxygen
5.9 : 5.9
Moles of Hydrogen : Moles of Oxygen = 1:1
Empirical Formula = OH
Để trung hòa 300 ml dung dịch có pH = 1 (chứa đồng thời HCl, HBr, HNO3 cùng nồng độ mol/l) cần dung dịch chứa 1,14 gam hh NaOH và Ca(OH)2 thu được dung dịch X. Khối lượng muối khan có trong X bằng
Answers
Answer:
2,405 g
Explanation:
[tex]nH^{+}[/tex] = 0,1 x 0,3 = 0,03 mol
Do dung dịch axit có nồng độ bằng nhau nên sô mol bằng nhau
⇒ n HCl = n HBr = n HNO3 = [tex]\frac{0,03}{3}[/tex] = 0,01
Do trung hào dung dịch axit nên n [tex]H^{+} = n OH^{-}[/tex] = 0,03
m Muối = m Axit + m Bazơ - m[tex]H_{2} O[/tex]
= 0,01 ( 36,5 + 81 + 63 ) + 1,14 - 0,03 x 18 = 2,405g
what is the molecular weight of H2so4?
Answers
Lets find
[tex]\\ \sf\longmapsto H_2SO_4[/tex]
[tex]\\ \sf\longmapsto 2(1u)+32u+4(16u)[/tex]
[tex]\\ \sf\longmapsto 2u+32u+64u[/tex]
[tex]\\ \sf\longmapsto 34u+64u[/tex]
[tex]\\ \sf\longmapsto 98u[/tex]
Please help!
Best answer with explanation will be marked brainliest.
Answers
Explanation:
I think it is d because it is a gas
How could you describe the changes that happen when carbon changes form from graphite to diamond
-it is a chemical change, but the intensive and extensive properties of carbon will be maintained
-it is a physical change, but the intensive and extensive properties of carbon will be maintained
-it is a chemical change, which could change some of the intensive and extensive properties of the carbon
-it is a physical change, which could change some of the intensive and extensive properties of the carbon
Answers
The correct answer is: it is a chemical change, which could change some of the intensive and extensive properties of the carbon.
To answer this question, we must bear in mind that a chemical change involves the breaking of bonds in a substance and subsequent rearrangement of atoms to form a new substance.
This is why we say that in a chemical change, new substances are formed. Another name for a chemical change is a chemical reaction.
Having said that, it is clear that as graphite changes to diamond, bonds are broken and carbon atoms are rearranged.
This rearrangement of atoms leads to different intensive and extensive properties for graphite and diamond. For instance, graphite conducts electricity but diamond does not conduct electricity. Also, diamond is much denser and harder than graphite. A physical change can not lead to change in some of the intensive and extensive properties of the carbon.
Learn more:https://brainly.com/question/8853712
HELP ME THIS IS FOR TODAY!!!!!
Answers
Answer:
4. 0.5 kilometers (1st option)
5. 0.1 00 liters (last option)
Explanation:
500 meters to kilometers
4.
1 kilometer = 1000 meters
We use the formula SBD (SMALL TO BIG DIVIDE) i hope this helps you
500 ÷ 1000
= 0.5 kilometers
5.
100 milliliter to liter
SBD
100 ÷ 1000
= 0.1 00 liters
what evidence have you discovered to explain how the fossil record provides relative ages? use the words: mass extinction, superposition, fossils, and relative age
Answers
Answer:
Relative dating is based on the positions of fossils in rock layers. Lower layers were laid down earlier, so they are assumed to contain older fossils. This gives the fossil an approximate age in years. Absolute dating is often based on the amount of carbon-14 or other radioactive element that remains in a fossil up until extinction.
Relative dating is a method of dating where the geologic events are arranged and the rocks are left behind in a sequence. They function on the basis of the stratigraphy and don't provide us with actual numeric data.
It provides us with the relative ages such as mass extinction the fossils are superimposed. It is based on the position of fossils in the layers of the rocks.Learn more about the discoveries to explain how the fossil record.
brainly.com/question/22311467.
A factor is an experiment that can change is a(n)
Answers
Answer:
Option 2 variable
Explanation:
Answer:
variable.
Explanation:
A variable is anything that can change or be changed. In other words, it is any factor that can be manipulated, controlled for, or measured in an experiment.
• 3. Using the following formula Force (N) = mass (kg) x acceleration
(m/s). How is the force of a 50kg being drops at 2m/s^2
o
Answers
Explanation:
Hope it helps.
Thank you
Can I please have help on a Timer
Answers
Answer:
cell
tissue
organ
organ system
Explanation:
the cell is the smallest
a tissue looks like a unit
an organ is multiple units
organ systems are the full body
When you leave a wine exposed to the air, the ethanol in it reacts to form what?
Answers
Answer:
(ethanol) into acetic acid or vinegar. When wine is exposed to the air, Oxygen in the air interacts with the wine. The wine changes colour and turns both white and red wines brown.
Explanation:
What series does the following compound belong to?
Answers
Answer:
B
Carboxylic acid
Explanation:
I'm not entirely sure, but this should be it
i will mark brainliest if you are correct
Which statement about pure substances and elements is correct?
a
All pure substances are elements.
b
All elements are pure substances.
c
Pure substances cannot be elements.
d
Elements cannot be pure substances.
Answers
The statement about pure substances and elements correct is all elements are pure substances ,therefore option (b) is correct .
What do you mean by the elements ?An element is a pure substance whose atoms all have the same number of protons.
Elements are the simplest chemical elements and thus can not be broken down through chemical reactions.
Characteristics of element -:
Elements cannot be broken down into simpler substances by the chemical reactions. Each element is represented by a unique symbol.The atomic number gives a distinct identity to a chemical element.The statement about pure substances and elements correct is all elements are pure substances ,therefore option (b) is correct .
Learn more about elements ,here :
https://brainly.com/question/13025901
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there are 3 isotopes of the element Gz: Gz-80,Gz-81,Gz-83. the average atomic mass of Gz is 82.74. what is the most abundant isotope of Gz? (please type the mass number only )
Answers
The most abundant isotope is Gz-83 because the average atomic mass of Gz is closer to 83.
The average atomic mass is defined as the weigthed mean of the isotopes.
The mass of the isotopes is 80, 81 and 83 uma, respectively.
As the average atomic mass (82.74uma) is closer to the atomic mass of Gz-83 than the mass of the other isotopes, you can interpretate that the most abundant isotope is Gz-83.
Learn more about average atomic mass in:
https://brainly.com/question/21536220