Answer:
V = 14m/s
Explanation:
velocity is the rate of change in displacement
V = (change in displacement)/time
V = (50 - (-20) )/5
V = (70)/5
V = 14m/s
Which of the following processes is exothermic? Group of answer choices Allowing meat to thaw after taking it out of the freezer Popsicle melting on a warm summer day Boiling water in a beaker to convert it to steam Rolling a ball up a hill Reacting hydrogen and oxygen gases to make water
Answer:
Reacting hydrogen and oxygen gases to make water
Explanation:
Exothermic means that energy is released into the environment, so let's go through the process of elimination.
Allowing meat to thaw after taking it out of the freezer - NO it is endothermic, and takes energy/heat from the environment to thaw.
Popsicle melting on a warm summer day - NO also endothermic, the opposite of exothermic.
Boiling water in a beaker to convert it to steam - NO because we need to add heat, so it doesn't release any energy.
Rolling a ball up a hill - NO, for a ball to roll up a hill, it needs energy from something else, so it's not exothermic.
Reacting hydrogen and oxygen gases to make water - YES this reaction makes new bonds, which releases energy, so this is exothermic.
Among the following choices reacting hydrogen and oxygen gases to make water is an exothermic reaction as it releases energy as new bonds are formed.
What is an exothermic reaction?An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.
In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.
Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.
Learn more about exothermic reactions,here:
https://brainly.com/question/10373907
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Explain the different between a molecule and a compound.
Answer:
-A molecule is the smallesr part is compound whereas a compound is the combination of two or more atoms in a fixed proportion by wiehgt.
- A glass of water is an example of compound but a small portion of water can be called molecule.
What is Mendeleev’s Periodic Law? How many elements were classified by Mendeleev?
Answer:
1.the law that the properties of the elements are periodic functions of their atomic numbers. Also called Mendeleev's law. (originally) the statement that the chemical and physical properties of the elements recur periodically when the elements are arranged in the order of their atomic weights.
Explanation:
2.Mendeleev’s Periodic Law states that the properties of elements are the periodic function of their relative atomic masses. Mendeleev arranged all 63 elements; which were discovered till his time; in the order of their increasing relative atomic masses in a tabular form. It is known as Mendeleev’s Periodic Table.
Which bond type is found in ammonium chloride. Select one: a. metallic b. covalent c. ionic
Answer:
ionic
Explanation:
In NH4Cl molecule, ionic bond is formed between NH4+ and Cl– ions, 3 covalent bonds are formed between N and three H atoms and one coordinate bond is formed between N and 1 H atom.
HOPE IT HELPS :)
PLEASE MARK IT THE BRAINLIEST!
Answer:
[tex]\boxed{\sf c. \ ionic}[/tex]
Explanation:
NH₄Cl is formed by an ionic bond between NH₄⁺ and Cl⁻ ions.
NH₄Cl (solid) ⇒ NH4⁺ (aqueous) + Cl⁻ (aqueous)
Air is an example of a mixture because the elements and compounds that make up air retain their individual properties. T or F
Answer:
True
Explanation:
This is true because no chemical bonding or change was involved only mechanical mixing.
take an onion and one jam bottle insert the roots of onion in the jam bottle for five days . after five days observe the growth in the roots of onion which is submerged in jam bottle. write observation here
Answer:
It is noticed that after five days, there is elongation of the root cells in the roots of onion in the jam bottle
Explanation:
It is noticed that after five days, there is elongation of the root cells in the roots of onion in the jam bottle. The growth of a plant is due to the availability of the growing and dividing cells in the meristematic regions of the apical meristems. (stem cells). This site are active site for elongation and differentiation of the stem tissues. In the apical meristem of the root cells, the cells have the potential to carry out mitosis and cell division repeatedly in order to generate newer cells for extension and development of stems and leaves. With each cell division, one cell remains in the meristem which the other increases in size and differentiate due to different genomic expression to form the meristem regions which eventually becomes the stem structure.
You work in the special effects department of a movie studio. You are
currently working on a superhero movie where the hero is very strong
and can punch through metal. For the next scene you need to replace a
6 inch by 6 inch square of a metal wall with a different material that will
crumble when the actor hits it. What could you use?
A. You could use Carbon(C)
B. You could use Potassium (k)
C. You could use Titanium (T)
D. You could use Manganese (Mn)
Answer:
The correct option is;
D. Manganese (Mn)
Explanation:
Manganese is very brittle, hard, iron like silvery-gray metal, that is difficult to melt. In air, Manganese slowly disintegrate in a similar manner to iron rusting in water
Manganese and iron have similar chemical and physical properties however manganese is more harder and more brittle than iron
A brittle material is one that easily breaks without deforming elastically
Therefore, manganese, due to its very iron like appearance and brittle nature will be suitable to replace the metal wall and crumble easily when the actor hits it.
Which of the following polyatomic ions will form an ionic compound with two sodium ions? CO32− HCO31− NO21− NO31−
Answer:
CO32−
Explanation:
We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.
When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;
2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)
Answer:
A). CO32−
Explanation:
The following water measurements were made: 18 mL of water were measured with a beaker, 128.7 mL of water were measured in a graduated cylinder and 23.45 mL of water were measured in a buret. All of these water samples were then poured together in one container. What total volume of water should be reported, when significant digits are taken into account?
Answer:
170 mL
Explanation:
The total volume to be reported should be 170 mL.
According to the significant rule in mathematical operations, final answers are usually reported to reflect the accuracy of the least accurate number.
In this case, the least accurate of all the volumes has zero significant digits after the decimal, hence, the final answer after the mathematical operation should also have no significant digits after the decimal.
18 + 128.7 + 23.45 = 170.15
Therefore, the total volume to be reported when significant digits are taken into account would be 170 mL.
Select the items that describe a chemical property below. Choose THREE correct answers.
1:Heated iron can be hammered into a sword.
2:A handwarmer gets warm when it is opened and exposed to air.
3:Propane ignites to heat a grill.
4:Cotton is dyed red to make a dress.
5:A cylinder in an engine uses gasoline to move pistons.
6:Maple syrup is thicker than water.
Answer:
2:A handwarmer gets warm when it is opened and exposed to air.
3:Propane ignites to heat a grill.
4:Cotton is dyed red to make a dress.
Explanation:
The definition of a chemical property is when a property of characteristic of a substance that is observed during a reaction in which a chemical has been changed
Using complete sentences, explain how to predict the products and balance the reaction between sulfuric acid and potassium hydroxide. H2SO4 + KOH ⟶
Answer:
The answer to your question is given below.
Explanation:
The reaction of sulfuric acid and potassium hydroxide is called neutralisation.
Neutralisation is a reaction involving an acid and a base which produces salt and water only.
For the react between sulfuric acid, H2SO4 and potassium hydroxide, KOH, we can predict the products obtained as follow:
H2SO4 + KOH —>
In solution, H2SO4 and KOH will dissociate as follow:
H2SO4(aq) —> 2H^+(aq) + SO4^2-(aq)
KOH(aq) —> K^+(aq) + OH^-(aq)
H2SO4 + KOH —>
2H^+(aq) + SO4^2-(aq) + K^+(aq) + OH^-(aq) —> K^+(aq) + SO4^2-(aq) + 2H^+(aq) + OH^-
H2SO4 + KOH —> K2SO4 + H2O
Now, we can balance the above equation as follow:
H2SO4 + KOH —> K2SO4 + H2O
There are 2 atoms K on right side and 1 atom on the left side. It can be balance by writing 2 in front of ko as shown below:
H2SO4 + 2KOH —> K2SO4 + H2O
There are 2 atoms of H on the right side and a total of 4 atoms on the left side. It can be balance by writing 2 in front of H2O as shown below:
H2SO4 + 2KOH —> K2SO4 + 2H2O
Now,the equation is balanced.
Answer:
Given the reactants, H2SO4 and KOH, we are asked to determine the product(s) of the reaction. Since H2SO4 is an acid and KOH is a base. This is a neutralization reaction, thus, the products are salt and water.
So, H+ from H2SO4 will react with OH- from KOH forming H2O. K+ will also react with SO4 2- forming K2SO4. Therefore, the balanced reaction will be:
H2SO4 + 2KOH ---> K2SO4 + 2H2O
Explanation:
Metal A reacts with oxygen to form an oxide.The oxide is dissolved in water to form a soluble hydroxide.What is the solution formed called and what is metal A
Answer:
The solution formed is called Barium hydroxide Ba(OH)2 and metal A is Barium
Explanation:
All basic oxides except BaO are insoluble in water
please someone explain this I dont get it at all. how do we know that the 4th electron came from 2p because it's at 4th ionisation? why is it talking about 3s?? how do overall know that aluminium is in group 3 from the table??? thanks
Consider the reaction of 2.5 grams of Li (s) reacting with 0.5 grams of N2 (g) to produce Li3N (s). A) How many total grams of Li3 N (s) would be produced? B) Which of the starting elements is the limiting reagent, and how many grams of the non-limiting reagent remain after the reaction has completed?
Answer:
A) The amount in grams of Li₃N produced is 1.243 g
B) N₂, is the limiting reagent
The mass of the non-limiting reagent, Li, remaining after the reaction is completed is 1.757 g
Explanation:
The given parameters are;
The mass of Li(s) = 2.5 grams
The mass of N₂ (g) = 0.5 grams
The chemical equation for the reaction can be presented as follows;
6 Li (s) + N₂ (g) → 2 Li₃N
Therefore, 6 moles of Li reacts with 1 mole of N₂ to produce 2 moles of Li₃N
The molar mass of Li = 6.941 g/mol
The molar mass of N₂ = 28.0134 g/mol
The number of moles of a reactant or product, n is given by the relation;
n = Mass of substance/(Molar mass of the substance)
For lithium, Li, n = 2.5/6.941 = 0.3602 moles
For Nitrogen gas, N₂, n = 0.5/28.0134 = 0.01785 moles
A) Given that 1 mole of N₂ to produces 2 moles of Li₃N
0.01785 moles of N₂ will produces 2×0.01785 = 0.0357 moles of Li₃N
The molar mass of Li₃N = 34.83 g/mol
The mass of Li₃N = 34.83 g/mol × 0.0357 moles = 1.243 g
B) 6 moles of Li reacts with 1 mole of N₂ to produce 2 moles of Li₃N
0.3602 moles will reacts with 1/6×0.3602 = 0.06003 mole of N₂
Therefore, N₂, is the limiting reagent and we have;
0.01785 moles of N₂ will react with 6×0.01785 = 0.1071 moles of Li
The number of of moles of Li left = 0.3602 - 0.1071 =0.2531 moles
The mass of lithium left = 0.2531 moles × 6.941 g/mol = 1.757 g
The mass of lithium remaining after the reaction is completed = 1.757 g.
Identify the type of energy described in each sentence. Tiles gravitational energy mechanical energy chemical energy electrical energy thermal energy nuclear energy radiant energy Pairs The body stores lipids ingested as fat and uses this energy when needed. arrowBoth (answer) A person's hat falls off and lands on the ground. arrowBoth (answer) A wave of water pushes a surfer to shore. arrowBoth (answer) A burner on a stove heats up a tea kettle. arrowBoth (answer) A power plant splits atoms to generate power for a city. arrowBoth (answer) A nerve sends an impulse to another nerve. arrowBoth (answer) A plant absorbs the Sun's rays to start the process of photosynthesis. arrowBoth (answer)
Answer:
The body stores lipids ingested as fat and uses this energy when needed-chemical energy
A person's hat falls off and lands on the ground- gravitational energy
A wave of water pushes a surfer to shore- mechanical energy
A burner on a stove heats up a tea kettle- thermal energy
A power plant splits atoms to generate power for a city- nuclear energy
A nerve sends an impulse to another nerve- electrical energy
A plant absorbs the Sun's rays to start the process of photosynthesis- radiant energy
Explanation:
Gravitational energy is energy stored by an object as a consequence of its height.
Mechanical energy is the energy that is possessed by an object due to its motion or due to its position.
Chemical energy refers to energy stored in chemical bonds in a substance.
Thermal energy is a form of energy that exists due to temperature difference between two bodies.
Nuclear energy refers to energy stored in the nucleus of an atom.
Electrical energy is a form of energy resulting from the flow of electric charge.
Radiant energy refers to energy that moves through vacuum without passing through a material medium.
write the formula of three compounds which you know and name the elements in them
Answer:
[tex]\boxed{\sf{view \ explanation}}[/tex]
Explanation:
Compound definition:
A compound is a chemical substance formed by two or more chemically bonded elements.
Three compounds:
Water is a compound with the formula [tex]\sf H_2O[/tex].
Two hydrogen atoms and one oxygen atom is present in one molecule of water.
Sodium chloride or table salt is a compound with the formula [tex]\sf NaCl[/tex].
One sodium atom and one chlorine atom is present in one molecule of sodium chloride.
Ammonia is a compound with the formula [tex]\sf NH_3[/tex].
In one molecule of ammonia, one nitrogen atom and three hydrogen atoms are present.
Answer:
See below
Explanation:
Three compounds are:
1) [tex]\mathrm {H_{2}SO{4}}[/tex] [Sulfuric acid]
The elements in this compound are hydrogen (H) , Sulfur (S) and Oxygen (O).
2) [tex]\mathrm {NaOH}[/tex] [Sodium hydroxide]
The elements in this compound are Sodium (Na) , Oxygen (O) and Hydrogen (H).
3) [tex]\mathrm {HCl}[/tex] [Hydrochloric acid]
The elements are Hydrogen (H) and Chlorine (Cl).
PLEASE PLEASE HELP!! A pipe drips at 155mL/day- convert this rate to gallons/day (1gal=3.785L)
1 mL =[tex]10^{-3}[/tex] L
so $155$ mL =$155\times10^{-3}$ L
Now, $1$ gallon = $3.785$ L , or $1$ L= $\frac1{3.785}$ gallons
so $155\times10^{-3}$ L= $155\times10^{-3}\times \frac{1}{3.785}=40.95\times 10^{-3}$ gallons
and this is for each day, so just divide by 1 (day) to get the ratw gallons/day
i.e. $40.95\times 10^{-3}$ gal/day
4 examples of ionic bonding identifying in each one the anion, the cation and demonstrate the ionic bonding by means of the electronegativity difference.
Answer:
Here are some examples
Explanation:
NaCl
Cation = Na⁺, Anion = Cl⁻; ΔEN = |0.93 - 3.16| = 2.23
MgS
Cation = Mg²⁺, Anion = O²⁻; ΔEN = |1.31 - 3.44| = 2.53
KBr
Cation = K⁺, Anion = Br⁻; ΔEN = |0.82 - 2.96| = 2.14
CaF₂
Cation = Ca²⁺, Anion = F⁻; ΔEN = |1.00 - 3.98| = 2.98
In each case, ΔEN > 1.6, so the compound is ionic.
If alkali A has a pH value of 13 and alkali B has a pH value of 9, explain which is most likely to be used in indigestion tablets as a remedy for excess stomach acid. *
Answer:
Alkalai B
Explanation:
B because its a weak alkali ie baking soda ph 8.3(sodium bicarbonate)which is used as a remeady of heartburns and stomach acids.
What is the PRECAUTION for an Irritant?
A star is estimated to have a mass of 2.0 x 10 ^36kg. Assuming it to be a sphere of average radius of 7.0 x 10 ^5 km. Calculate the average density of the star in g/cm^3 and in lb/ft^3
Answer:
a) 1.392 x 10^6 g/cm^3
b) 8.69 x 10^7 lb/ft^3
Explanation:
mass of the star m = 2.0 x 10^36 kg
radius of the star (assumed to be spherical) r = 7.0 x 10^5 km = 7.0 x 10^8 m
The density of substance ρ = mass/volume
The volume of the star = volume of a sphere = [tex]\frac{4}{3}\pi r^{3}[/tex]
==> V = [tex]\frac{4}{3}*3.142*(7.0*10^8)^{3}[/tex] = 1.437 x 10^27 m^3
density of the star ρ = (2.0 x 10^36)/(1.437 x 10^27) = 1.392 x 10^9 kg/m^3
in g/cm^3 = (1.392 x 10^9)/1000 = 1.392 x 10^6 g/cm^3
in lb/ft^3 = (1.392 x 10^9)/16.018 = 8.69 x 10^7 lb/ft^3
The number of atoms in 2.0 moles of NaOH is _____ of 1.0 mole of H2O.
twice that
less than
more than
the same as
Answer:
The answer is the same as .
Explanation:
There are 3 atoms in NaOH, 1 sodium, 1 oxygen and 1 hydrogen.
There are 3 atoms in H2O, 2 hydrogen and 1 oxygen.
3.87 moles of iron bromide yielded10.4 moles of sodium bromide
Answer: 89.57 %
Hope it helps
list one difference between blended fibres and regenerating synthetic fibres
Answer:
blended is better than synthetic fibre. because blended fabrics have quality of synthetic and natural fibres so they are more better than fabrics. For example terrycot. Blended Fibres are considered better than individual synthetic fibres because they show the advantages of 2 or more fibres.
In the molecule 4H2O2 the number of hydrogen atoms is what
Answer:
Scientists
Explanation:
Scientists because they are the one who makes hypothesis.
Ag2S + Al(s) = Al2S3 + Ag(s) (unbalanced)
1) What would the overall potential for this cell be?
2) Write the standard cell notation for an electrochemical cell consisting of an anode and cathode of the same types as in this experiment, connected through a salt bridge.
Answer:
1. 0.97 V
2. [tex]Al_(_s_)/Al^+^3~_(_a_q_)~//~Ag^+~_(_a_q_)/Ag_(_s_)[/tex]
Explanation:
In this case, we can start with the half-reactions:
[tex]Ag^+~_(_a_q_)->~Ag_(_s_)[/tex]
[tex]Al_(_s_)~->~Al^+^3~_(_a_q_)[/tex]
With this in mind we can add the electrons:
[tex]Ag^+~_(_a_q_)+~e^-~->~Ag_(_s_)[/tex] Reduction
[tex]Al_(_s_)~->~Al^+^3~_(_a_q_)+~3e^-~[/tex] Oxidation
The reduction potential values for each half-reaction are:
[tex]Ag_2S~+~e^-~->~Ag_(_s_)~+~S^-^2~_(_a_q_)[/tex] - 0.69 V
[tex]Al^+^3~_(_a_q_)+~2e^-~->~Al_(_s_)[/tex] -1.66 V
In the aluminum half-reaction, we have an oxidation reaction, therefore we have to flip the reduction potential value:
[tex]Al_(_s_)~->~Al^+^3~+~2e^-~[/tex] +1.66 V
Finally, to calculate the overall potential we have to add the two values:
1.66 V - 0.69 V = 0.97 V
For the second question, we have to keep in mind that in the cell notation we put the anode (the oxidation half-reaction) in the left and the cathode (the reduction half-reaction) in the right. Additionally, we have to use "//" for the salt bridge, therefore:
[tex]Al_(_s_)/Al^+^3~_(_a_q_)~//~Ag^+~_(_a_q_)/~Ag_(_s_)[/tex]
I hope it helps!
Undulation in sandy material is called
cross-beds
ripple marks
mud cracks
O fossils
Answer:
ripple marks
Explanation:
Undulation is defined as the to and fro wavelike motion in a fluid or elastic medium.
Undulation in sandy material is called ripple marks because ripple marks are the sediments of rocks that show wavy structure at its surface due to agitation by water and wind.
Hence, the correct answer is "ripple marks".
how to unscramble dtneinreigs
Answer:
Ingredients OR tenderising
Explanation:
The recommended dose of aminophylline for children is 1.0 mg/kg/hr. 15 mL of a 30 mg/mL sltn is added to a 150 mL bottle of D5W. At what rate mL/hr should the injection be delivered to 35 lb child
Answer:
The answer is "6.68 [tex]\frac{ml} {hr}[/tex]".
Explanation:
It's going to be 18.18 kg to turn body mass to kg.
Size 1mg / kg / hr, therefore = 1 x 18.18
= 18.18 kg / hr
now we adding 30 mg / ml of dextrose = 30 x 15
[tex]=\frac{450mg}{15 ml +150 ml}[/tex]
of dextrose, from 15 ml to 150 ml;
Therefore, now 450 mg in 165m:
[tex]= \frac{ 450}{165}\\ \\=2.72 \frac{mg} {ml}[/tex]
now divide the 18.18 by 2.72:
[tex]=\frac{18.18}{2.72}[/tex]
= 6.68 [tex]\frac{ml} {hr}[/tex]
H2SO4 is also called
a. king of acid
b. king of chemical
c. blue vitriol
d. Antacid
Answer:
[tex]\huge\boxed{King\ of \ Acid}[/tex]
Explanation:
H2SO4 (also called sulfuric acid) is also called King of Acids. It is a highly reactive acid.
Answer:
[tex]\large \boxed{\mathrm{a. \ king \ of \ acid }}[/tex]
Explanation:
[tex]\sf H_2SO_4[/tex] or sulfuric acid is known as the king of acid. It is a very reactive acid and is a strong acid in general.
