Answer:
they are much cheaper and because thy last for a long time as they are durable and not expensive
because LED use less energy than torch bulb
LED use more than 75% less energy than torch bulb
What is the molecular formula for a compound with an empirical formula of C₅H₄ and a molar mass of 128.16g?
Answer:
[tex]C_{10} H_{8}[/tex]
Explanation:
Molecular formula can be calculated by finding the ratio of the molecular molar mass to the empirical molar mass, then multiplying the subscripts of the empirical molar mass by that ratio.
The empirical molar mass is 5(12.01) + 4(1.01) = 64.09g
The molecular molar mass is 128.16g
128.16/64.09 = 2
So the molecular formula is [tex]C_{10} H_{8}[/tex]
New evidence can cause scientists to revise a scientific theory. If new evidence comes to
light, which is most likely to happen?
Answer: after years of research if the evidence still supports a change the theory will be revised
Explanation:
I think that’s it
Calculate heat energy
Answer:
The equation for calculating heat energy is q=mCpΔT, where q is the heat variable, m is the mass of the object, Cp is the specific heat constant and ΔT is the temperature change.
Explanation:
10. pls pls help me
Answer:
2c2h2+502=4co2+H2O
Explanation:
this is the answer
is lung cancer a physical property or chemical property?
Answer:
its a chemical property
Explanation:
Item 3
Which statement describes the electrical conductivity of metals and semiconductors? Choose the correct answer.
Metals are poor conductors at low temperatures.
The conductivity of metals changes with changing pressure.
The conductivity of semiconductors changes with changing pressure.
Semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.
Answer:
Semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.
Explanation:
A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;
1. Extrinsic semiconductor.
2. Intrinsic semiconductor.
The statement which best describes the electrical conductivity of metals and semiconductors is that semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.
This ultimately implies that, semiconductors are typically an insulator (poor conductor) at low temperatures and a good conductor at high temperatures.
Additionally, conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.
Which statement best describes the main conflict in "Wiley, His Mother, and the Hairy Man"?
Answer:
a. Wiley has to find a way out of the tree he ran up.
b. Wiley has to trick the Hairy Man into turning himself into animals.
c. Wiley has to ask his mama for help to defeat the Hairy Man.
d. Wiley has to defeat the Hairy Man three times to make him go away.
Answer:
Wiley has to defeat the Hairy man three times to make him go away
Explanation:
What equation is used to calculate the pH of a solution?
Answer:
pH = -log[H3O+] or pH = -log[H+]
Explanation:
pH is the negative log of hydronium concentration or hydrogen ion concentration. The two are essentially interchangeable.
1) What is the mass in grams of a 51.2-mole sample of calcium?
Answer:
2051.9936 g
Explanation:
Mass = ?
Number of moles = 51.2 mol
The relationship between both quantities is given by the equation;
Number of moles = Mass / Molar mass
Solving for mass;
Mass = Number of moles * Molar mass
Mass = 51.2 * 40.078
Mass = 2051.9936 g
Which of the following statements is true? Running an electric current through a magnet can create a magnetic field, Electrons are found in the nucleus of an atom, The strength of a magnetic field increases with distance, Electric engines change electricity into magnestism
Answer:
running an electric current through a magnet can create a magnetic field
Describe the distribution of mass within an atom
Answer:
The nuclei of most atoms also contain neutrons . The masses of subatomic particles are very tiny. ... Since the nucleus contains protons and neutrons, most of the mass of an atom is concentrated in its nucleus. Protons and electrons have electrical charges that are equal and opposite.
There are 2 places where charge is located in the atom:
the nucleus contains neutrons (zero charge) and protons (positive charge)
Around the nucleus there are electrons located on electron shields and the charge of electrons is equal to the charge of protons in the nucleus, but have negative sign.
To sum it all up we can say that the charge of protons in the nucleus is reduced by the charge of electrons on the orbits to make the atom electrically neutral.
Which of the following is NOT a feature found on the Moon?
A. Mountains
B. Valleys
C. Craters
D. Oceans
Answer:
D
Explanation:
no water fjkdbksfjgnkfjgdkufgkjdfghkdfjhdgfg
what is a ecosystem. A. a squirrel and it physical surroundings. B.a squirrel and what it does. c. all squirrels. d.one squirrel. GIVE BRANLIYST
Explanation:
A system formed by the interaction of a community of organism with their physical environment is called ecosystem.
A. a squirrel and it physical surroundings.
At 10C, 100g of H2O can dissolve only 78g of NaNO3
1.If we have 50g of NaNO3, in 100g of water at 10C the solution is?
2.If we have exactly 78g of NaNO3 in 100g of water at 10C the solution is?
3.What will happen if we add 80g of NaNO3 in 100g of water at 10C?
4) 40C we can dissolve 94g of NaNO3 in 100g of water. What will happen if the solution is cooled to 10C?
Answer:
The given parameter for the solubility of NaNO₃ in H₂O are;
The maximum solubility of NaNO₃ in H₂O at 10°C = 78 g
1. If we have 50 g of NaNO₃ in 100 g of water at 10°C, the solution is;
Undersaturated
2. If we have exactly 78 g of NaNO₃ in 100 g of water at 10°C the solution is;
A saturated solution
3. If will add 80 g of NaNO₃ in 100 g of water at 10°C,
The excess NaNO₃ which cannot be dissolved will be observed as solids in the mixture
4) The quantity of NaNO₃ that can be dissolved in H₂O at 40°C = 94 g
If the solution containing 94 g of NaNO₃ at 40°C is cooled to 10C about 16 g of NaNO₃ will precipitate out of the solution and exist as solids in the mixture
Explanation:
1. An undersaturated is a solution that holds smaller amount of solute that it can hold at a given temperature
2. A saturated solution holds as much solute as it can dissolve at a given temperature
3. When more solutes are added to a saturated solution, the excess solution will remain in the solid form in the mixture
4) Cooling a saturated solution below the saturation temperature will result in the precipitation or crystallization of the excess solutes in the solution.
Dalton's contribution was different from thatof the ancient Greeks who populated the existence of atoms.Point out the difference between the two ideas.
Answer:
See explanation
Explanation:
The Greeks held the belief that atoms where spherical. However, they thought that atoms of elements where different for the different states of mater. Dalton brought about the idea that the atoms of the same element are exactly alike irrespective of the physical state of the system.
Dalton introduced the idea that chemical reactions result from rearrangement of atoms in molecules. This idea was not captured by the early Greeks.
A chemical reaction can theoretically produce 137.5 grams of product, but it actually produced 112.9 grams. Which is the percent yield for this reaction? AKS 4f
Answer:
Explanation:
Zoom in we can't see it dude
A gas has a solubility of 1.46 g L at 8.00 atm of pressure. What is the pressure of a sample of the same gas that
contains 2.7 g/L of the dissolved gas?
Answer:
[tex]14.8\ \text{atm}[/tex]
Explanation:
[tex]C_1[/tex] = Initial concentration = 1.46 g/L
[tex]C_2[/tex] = Final concentration = 2.7 g/L
[tex]P_1[/tex] = Initial pressure = 8 atm
[tex]P_2[/tex] = Final pressure
From Henry's law we have the relation
[tex]\dfrac{C_2}{C_1}=\dfrac{P_2}{P_1}\\\Rightarrow P_2=\dfrac{C_2}{C_1}P_1\\\Rightarrow P_2=\dfrac{2.7}{1.46}\times 8\\\Rightarrow P_2=14.8\ \text{atm}[/tex]
The pressure of a sample of the same gas at the required concentration is [tex]14.8\ \text{atm}[/tex].
An advantage of cooking in steam is .
A. it is faster than boiling when pressure is added
B. foods are more flavorful
C. foods are more nutritious
D. All of the above.
Answer:
The answe is all of the above
How many mililiters are in 0.5000 liters?
Question 6 options:
50 ml
500 ml
0.5000 ml
5,000 ml
What type of decay does Am-241 undergo to become Np-237?
a. Alpha decay
c. Positron emission
b. Beta decay
d. Electron capture
The type of decay that Am-241 undergoes to become Np-237 is alpha decay. The correct option is a.
What is alpha decay?Alpha decay is a type of decay or transformation in which a nucleus emits an alpha particle and change into different atomic nuclei. The atomic number reduces by 2 and the mass is reduced by 4.
Am-241 is an isotope of the chemical element americium. It is a radioactive element and its radioactive decay period is 432.2 years. It is used in the testing of machinery.
When the nucleus of Am changes or emits a radioactive particle. It converts into Np-237. The process is called alpha decay. The atomic mass is reduced by four, and the 241 converts into 237, which become neptunium.
Thus, the correct option is a. Alpha decay.
To learn more about alpha decay, refer to the link:
https://brainly.com/question/27870937
#SPJ2
PLS ANSWER FAST WILL GIVE BRAINLY!!!!
dissolving sugar into coffee is a chemical change
true or false
Which of the following is considered parasitism?
a
A hummingbird pollinating a flower.
b
A flea is sucking the blood from a dog.
c
A spider builds its web in a tree.
d
A bug hitches a ride on your backpack during a hike.
La leche se considera un alimento basico por su elevado contenido de nutrientes su densidad es de 1,4g/ml. Si se hace una compra de 7 bolsas de leche cada una con un volumen de 900m cual es la masa total de la leche expresada en kilogramos?
Answer:
8.82 kg es la masa total de leche
Explanation:
Consideraremos que el volumen de cada bolsa de leche es de 900 mL.
Sabiendo que tenemos en total 7 bolsas, el volumen final en litros que tenemos disponible es de:
900 mL . 7 = 6300 mL
Utilizando la densidad podemos calcular la masa de leche que tenemos en el total de las 7 bolsas
Densidad = masa / volumen
Densidad . volumen = masa → 1.4 g/mL . 6300 mL = 8820 g
Convertimos la masa de gramos a kg
8820 g . 1 kg /1000g = 8.82 kg
The equation below shows the decomposition of lead nitrate. How many molecules of PbO are produced when 11.5 g NO2 is formed?
2Pb(NO3 )2 (s) → 2PbO(s) + 4NO2 (g) + O2 (g)
connect them, dont guess please + 23 points
Answer:
Astronaut- highly trained individual for space travel
Payload Specialist- partnering scientist, journalist, or political guest.
Space Sickness- nausea, vomiting, and upset stomach.
Muscle Atrophy- the result of microgravity.
Johnson Space Center- training facility for U.S. astronauts.
connect them please, dont guess ill give brainiest to the FIRST answer + 29 points
Answer:
I cant see it sorry
Explanation:
Post another one
which process helps guarantee that a species continues to involve over hundreds of years?
A. growth
B. nutrition
C. reproduction
Answer:
C. reproduction
Explanation:
In a combustion reaction, pentane (molar mass (MM) = 72.17 g/mol) burns, in the presence of oxygen (MM = 32.00 g/mol), to produce carbon dioxide (MM = 44.01 g/mol) and water (MM = 18.02 g/mol).
The balanced reaction is shown here: C5H12 (l) + 8 O2 (g) à 5 CO2 (g) + 6 H2O (g)
If 4.0 mol of O2 is available, what is the maximum number of moles of water that can be produced (AKS 4f)?
A.
3.0 mol
B.
4.0 mol
C.
5.0 mol
D.
8.0 mol
E.
2.0 mol
The maximum number of mole of water that can be produced is 3 moles (Option A)
Balanced equationC₅H₁₂ + 8O₂ —> 5CO₂ + 6H₂O
From the balanced equation above,
8 moles of O₂ reacted to produce 6 moles of H₂O
How to determine the mole of water producedFrom the balanced equation above,
8 moles of O₂ reacted to produce 6 moles of H₂O.
Therefore,
4 moles of O₂ will react to produce = (4 × 6) / 8 = 3 moles of H₂O.
Thus, we can conclude that the maximum mole of water produced is 3 moles
Learn more about stoichiometry:
https://brainly.com/question/14735801
someone please do this!!!
Answer:
1) Fe = 69.9%
O = 31.1%
2) H = 5.19%
O = 16.5%
N = 28.9%
C = 49.5%
Explanation:
One easy way to do percent compositions is to assume you have 100g of a substance.
1) Lets say we have 100g of Fe2O3.
The total molar mass would be:
[tex]= 55.845*2+15.999*3 = 159.687[/tex]
The molar mass of the Fe2 alone is:
[tex]=55.845*2 = 111.69[/tex]
Thus, the grams of Fe2(out of a 100) could be calculated by multiplying 100g * the molar mass ratio of Fe2 to the whole:
[tex]= 100g *\frac{111.69}{159.687} = 69.9431[/tex]
Which is approximately 69.9%.
We can find the amount of O3 by simply subtracting, as the rest of the compound is made of O3. Thus, the % composition of O3 is 31.1%
You can then do this same process to the next question, getting us the following:
H = 5.19%
O = 16.5%
N = 28.9%
C = 49.5%
HELPPPP!!! I need the CORRRECT answer
1.Which pair of properties describes the elements in Group 18?
a) They are gasseous at room tempature and chemically stable
b) they have 8 valence electrons and are stable
c) they are chemically stable and liquid at room tempature
d) they are magnetic and boil at room tempature
Answer: c
Explanation: