Answer:
substance
Explanation:
A pure substance is a form of matter that has a constant composition (meaning it's the same everywhere) and properties that are constant throughout the sample (meaning there is only one set of properties such as melting point, color, boiling point, etc
How many formula units are in 9.8 grams of calcium hydroxide?
Answer:
There are 9.8 ×1021. formula units in 10,005.8gCaO
Balance the following equation: N2 + H2 --> NH3
Write the coefficients that you decide balance the equation like this 3, 4, 3. If you do not add a coefficient in front of an element or compound, use a 1 in your answer. For instance the for this balanced equation: 2H2 + O2 --> 2H2O you would write your answer: 2, 1, 2
Answer:
3, 2
Explanation:
Balanced equation:
N2 + 3 H2 = 2 NH3
What ratio of NaCN to HCN is needed to prepare a pH 9.40 buffer? (Ka of HCN is 4.9 × 10⁻¹⁰)
Answer: The ratio of NaCN to HCN is, 1.26
Mg + 2HCl ⟶ MgCl2 + H2
How many grams of MgCl2 are produced by 2.55 mol Mg?
Answer: m = nM= 242.8 g
Explanation: amount of MgCl2 is same as n(Mg)
M(MgCl2) = 95.21 g/mol
95.21 g/mol is the mass in grams of MgCl[tex]_2[/tex] are produced by 2.55 mol Mg in the reaction Mg + 2HCl ⟶ MgCl[tex]_2[/tex] + H[tex]_2[/tex].
What is mass?A body's mass is an inherent quality. Prior to the discoveries of the concept of atom as well as particle physics, it was widely considered to be tied to the amount of matter inside a physical body. It was discovered that, despite having the same quantity of matter in theory, different atoms and elementary particles have varied masses.
There are various conceptions of mass in contemporary physics that are theoretically different but physically equivalent. The resistance of the body to accelerate (change of velocity) in the presence of a net force can be measured experimentally as mass. The gravitational pull an object has on other bodies is also influenced by its mass.
m = n×M= 242.8 g
M(MgCl[tex]_2[/tex]) = 95.21 g/mol
Therefore, 95.21 g/mol is the mass in grams of MgCl[tex]_2[/tex] are produced by 2.55 mol Mg in the reaction Mg + 2HCl ⟶ MgCl[tex]_2[/tex] + H[tex]_2[/tex].
To know more about mass, here:
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Help me please I’ll give brainliest answer
Answer:
the answer is c I believe
type a question about gas starting with “what if”
Answer:
what if we didn't have gas
Explanation:
A tall plant (Tt) is crossed with a short plant (tt). What percent will be short?
Group of answer choices
75%
0%
100%
50%
25%
it should be 50/50 percent
so 50%
hopefully this is right !
N2-3H2 → 2NH3
How many moles of hydrogen, H2, are needed
to react with 2.0 moles of nitrogen, N2?
Answer:
6 mols H2 are needed
Explanation:
N2 = 28.01g/mol
H2 = 2.02g/mol
[tex]\frac{2 mol N_{2} }{1}[/tex] * [tex]\frac{3 mol H_{2} }{ 1 mol N_{2} }[/tex] = 6 mol H2
In a chemical reaction, there is more matter in the reactants than in the products true or false
Answer:False
Explanation:Law of Conservation
Citric acid and rennet are added to milk to make cheese. What is the evidence that this is a
chemical reaction?
gas production
formation of a precipitate
light is released
color change
Answer:
formation of a precipitate.
Explanation:
This is because during production of cheese, citric acid is added to raise the acid level and rennet is added as an enzymes. This make the milk to coagulate and form solid and semi solids. Some part become solid part which is the cheese and the water is separated and it is called whey. That is it separated the solid from the liquid part . The precipitate is the solid part.
Something that has all the characteristics of lif
Answer:
humans or animals
Explanation:
wont more BRAINLYS just answer the question right
Answer:
1. A.
2. D.
3. E.
4. B
5. C.
Explanation:
1. The water cycle uses radiant energy from the sun to function
2. Crystals form by crystalization, hence the name.
3. Condensation is when water vapor changes to a liquid.
4. The water cycle is the movement of water on earth on and below it's crust.
5. Transperation is how plants release water into the air. Also how humans sweat.
Have a most wonderous day!
Calculate the concentration of a 220 g solution of calcium chloride (CaCl2) that has a volume of 11 L
Answer: The concentration of the solution is 0.18 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in L
moles of [tex]CaCl_2[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{220g}{111g/mol}=1.98mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]Molarity=\frac{1.98mol}{11L}=0.18M[/tex]
Therefore, the concentration of the solution is 0.18 M
Which element would be the most suitable to make a spoon that will melt in
your hot drinks?
A) aluminium
melting point: 660°C
boiling point: 2470°C
B) argon
melting point: -189°C
boiling point:-186°C
C) bromine
melting point: -7°C
boiling point: 59°C
D) gallium
melting point: 30°C
boiling point: 2400°C
E) lithium
melting point: 180°C
boiling point: 1330°C
F)mercury
melting point: -39°C
boiling point:357°C
Answer:
it's A) or E)
others are not suitable cuz their melting point is weak.
Answer:
Gallium
Explanation:
Because the melting point is low and the drinks are usually around 60-70 degrees Celsius so it wil melt
Which is the correct number of moles of nitrogen monoxide that is produced from 13.2 moles of oxygen gas in the presence of excess ammonia (NH3)?
Answer:
10.56 moles of NO will be produced
Explanation:
The balanced reaction of ammonia, NH₃ with oxygen, O₂ is:
4NH₃ + 5O₂ → 4NO + 6H₂O
Where 5 moles of oxygen react with an excess of ammonia to produce 4 moles of nitrogen monoxude.
If 13.2 moles of O₂ react:
13.2 mol O₂ * (4 mol NO / 5 mol O₂) =
10.56 moles of NO will be producedPLZ HELP ME. I NEED ANSWER ASAP!!!!!!
Which of the following is not true regarding an acid?
Select one:
a. can accept a proton (H+) from some other substance
b. neutralizes hydroxide ions to form water
c. can donate a proton (H+) to some other substance
Answer:
Answer 'A'
Explanation:
There are 3 acid-base theories.
- Arrhenius Theory
- Bronsted-Lowry Theory
- Lewis Theory
In the Arrhenius and the Bronsted-Lowry Theories, for an acid to be an acid two requirements must be met. That is, the substance must be soluble in water and two, undergo ionization generating a hydronium cation (H₃O⁺) and a base anion (A⁻) in process; i.e., H-Anion + H₂O => H₃O⁺ + Anion⁻.
The Lewis Theory defines acids and bases in terms of electron pair donation (the base) and electron pair acceptor (the acid). This theory does not require the presence of an ionizable hydrogen in the substance of interest, only non-bonded electron pairs (base) and a cationic character that accepts electron pairs without violating the octet rule in chemical bonding.
For the purpose of answering your question, the Arrhenius and Bronsted-Lowry theories are sufficient for defining acids and bases undergoing ionization in aqueous media. With this, one should understand also that acids and bases are classified as strong acids and strong bases (compounds that ionize 100% aqueous media) or weak acids and weak bases (compounds that do not ionize 100% in aqueous media).
Strong Acids* include HCl, HBr, HI, HNO₃, HClO₄ & H₂SO₄ (1st ionization step only). Strong Bases include Group IA and Group IIA hydroxides except for Beryllium Hydroxides. The weak acids are compounds with ionizable hydrogens that are NOT members of the strong 6 listed above. The weak bases are ammonia and ammonia derivatives in aqueous media.
It is recommended that students only need to memorize the strong six acids in that any compound not one of these six with an ionizable hydrogen is a weak acid whether you know its name or not. The weak bases, as mentioned, are ammonia and ammonia derivatives in water. These compounds will undergo coordinate bonding to generate an ionizable compound containing an ammonium cation and hydroxyl anion. The reaction is as follows:
RNH₂ + H₂O => RNH₃⁺OH⁻(aq) => RNH₃⁺(aq) + OH⁻(aq)
Typically, weak acids and weak bases undergo very limited ionization in the range of 1% to 2%. The compounds remaining are in concentrations of 98% - 99% unionized but form soluble homogeneous solutions.
If you have further questions, kick back a note. Doc
___________________-
*Some scholars include sulfurous acid (H₂SO₃) as a strong acid but analysis shows aqueous solutions - under special conditions - to contain unionized H₂SO₃ and thus violates the 100% ionization requirement.
Directions Identify the reactants and product in the following reaction.
4A1+302 → 2A1203
What might happen if 490 g of sugar is dissolved in water at 100°C and then the water cools to 20°C?
Answer:
crystallization
Explanation:
When 490g of sugar is dissolved completely in water at a high temperature ( 100°C ) and the solution is been cooled to a lower temperature ( 20°C ), The dissolved sugar in the solution will start to crystallize, This is because the solubility of sugar in water decreases with a decrease in temperature of water.
How many milliliters of an aqueous solution of 0.238 M iron(III) chloride is needed to obtain 18.8 grams of the salt?
_______mL
Explanation:
Salt?%$- RICE BUTTRESS Ê TCHAIKOVSKY
I went for a walk the other day. I went four blocks east, then seven blocks south, then one block west and finally
eight blocks north
a.What distance did I travel?
b. What's my displacement?
Answer:
a) distance is 4+7+1+8=20 blocks
b) displacement is 10 blocks
Explanation:
find displacement: x and y
x axis displacement = 4-1 = 3 blocks
y axis displacement = -7+8= 1 block
displacement = the square root of 3^2 + 1^2
= 9+1 = 10 blocks.
You can find the angle of displacement with respect to the initial position using trig identities, if you wish.
Pls 50 points right answer gets brainliest
Explain the meaning of thermal energy transfer and give specific examples of conduction, convection, and radiation.
Answer:
thermal energy: the part of total internal energy that can be transferred (a portion of the kinetic energy)
heat is the thermal energy that flows from one substance to another due to a temperature difference.
Thermal energy is measured in temperature change.
Thermal energy transfer stops when thermal equilibrium is achieved (Both substances at the same temperature).
conduction: Transfer of thermal energy through a solid object like heat transferring up a metal spoon from a hot cup of coffee.
convection: the transfer of thermal energy due to the movement of a liquid or gas caused by differences in temperature. Only in a fluid (liquid or gas). Breezes, ocean currents.
radiation: Transfer energy with or without matter. Warming from the Sun, microwave oven.
Answer:
Conduction is the transfer of thermal energy through direct contact. Convection is the transfer of thermal energy through the movement of a liquid or gas. Radiation is the transfer of thermal energy through thermal emission. Hope this helps!
Explanation:
in the rainforest, plants that live on the forest floor have different adoptions from plants that live high up in the canopy. what is the main reason that leaves of plants on the rain forest floor are much wider than those found higher in the canopy of the rain forest?
1: these plants produce poisons that plants in other area do not.
2: these plants have less access to light then plants in other areas.
3: These plants need to take in more water than plants in other areas.
4: these plants have more natural predators then plants in other areas.
Answer:
option 3, the leaves higher up need less water since there getting more light and the ones lower need to adapt to gaining more water since they won't be seeing much light
Temperature, according to the kinetic molecular theory, is a measure of intermolecular attraction.
TRUE or FALSE
choose the correct one
Answer:
B. More reactant is added.
Explanation:
The question basically asks at which condition would the forward reaction be favoured.
The law of equilibrium states when a system at equilibrium is disturbed by, it would annul that change. In order to increase the forward reaction, more of the reactant should be added. In order to annul this change, the system would have to favour the reaction that deals with reducing the amount of reactant added.
The correct option is;
B. More reactant is added.
Explain how a long-term environmental change can lead
to the development of a new species.( its a paragraph
Answer:
Humans are modifying the world in many ways, and not all of them for the better. The changes we cause are often severe challenges to animals, plants and microbes in nature, from the introduction of pathogens or exotic invasive species to adding toxic substance or excessive nutrients, or causing climatic change. Often several changes occur at once. Nelson Hairston's lab focuses on freshwater environments, especially lakes and ponds, where some of the species present respond to environmental change with decreases in their numbers, even to the point of extinction, while others may benefit to excess, becoming so dominant that they present problems, as in the case of harmful algal blooms stimulated by nutrient enrichment or climate warming. Hairston's lab studies how individual species, food webs, and whole ecosystems are altered when the environment changes.
One way that some freshwater organisms respond to environmental change is to evolve rapidly. A marked change in the environment favors some characteristics of plants, animals and microbes over others. These character differences are often genetically based so that favored characteristics may increase in the next generation. The shorter the generation time, the faster this evolutionary change can occur. For example, tiny but abundant plankton, eaten by fish and other larger animals, can become adapted to the changed environment within a few years because their generation time is only a few days. Hairston's lab has shown that planktonic "water fleas" (Daphnia), major consumers of suspended algae in lakes, evolved to be tolerant of harmful algae within a decade of the appearance of blooms. This rapid evolution (termed "evolutionary rescue" in conservation biology) raises many intriguing questions, for all environments, not just freshwater: To what extent can we rely on species adapting rather than going extinct when their environment changes? How does the evolution of a species that plays a critical ecological role alter the interactions it has with other species, and the functioning of the entire ecosystem?
Blood is a mixture of cells and a liquid called
plasma, which is;
produced in the bone marrow.
a lymphoid tissue.produced in the spleen.
mostly water.
Answer:
mostly water
Explanation:
just did he test on edg
Please help as soon as possible please and thank you.
Large drops of rain form in a cumulonimbus cloud are started by______.
Select one:
a. small rain droplet colliding with others and forming larger drops
b. hail stones melting
c. water vapor condensing in larger quantity
Answer:
The answer is A. I took the test today.
Explanation:
what is the period of sulfur is.
Answer:
Sulfur is the 16th element on the periodic table which is located in period 3 and group 16.
Explanation:
Which material serves as an inert electrode in an alkaline dry cell?
A. copper
B. platinum
C. graphite
D. zinc
Answer:
B
Explanation:
Answer:
i put platinum in edge
Explanation:
Edge doesnt give correct answers on unit tests, but i passed with an 88 :)
4. Given the balanced equation: 2Na + S → Na₂S
How many grams of sulfur are needed to react with 43 grams of Na? Round to the nearest whole number.
a. 119 g
b. 158 g
c. 32 g
d. 30 g
Answer:
Option D. 30 g
Explanation:
The balanced equation for the reaction is given below:
2Na + S —> Na₂S
Next, we shall determine the masses of Na and S that reacted from the balanced equation. This is can be obtained as:
Molar mass of Na = 23 g/mol
Mass of Na from the balanced equation = 2 × 23 = 46 g
Molar mass of S = 32 g/mol
Mass of S from the balanced equation = 1 × 32 = 32 g
SUMMARY:
From the balanced equation above,
46 g of Na reacted with 32 g of S.
Finally, we shall determine the mass sulphur, S needed to react with 43 g of sodium, Na. This can be obtained as follow:
From the balanced equation above,
46 g of Na reacted with 32 g of S.
Therefore, 43 g of Na will react with = (43 × 32)/46 = 30 g of S.
Thus, 30 g of S is needed for the reaction.