What are some true statements about light​

Answers

Answer 1

Answer:It allows us to see things so we know where we are going that’s why at night we had lamp posts

Explanation:


Related Questions

How many grams of H2 can be produced from the reaction of 11.50 g of sodium with an excess of water? The equation for the reaction is 2 Na + 2 H2O -> 2 NaOH + H2 Ans: 0.504 2 g H2 I would like to know how to solve this problem, the teacher gave me the answer but I am unsure how to solve it thanks!

Answers

Answer:

[tex]m_{H_2}=0.504gH_2[/tex]

Explanation:

Hello,

In this case, since the reaction is:

[tex]2 Na + 2 H_2O \rightarrow 2 NaOH + H_2[/tex]

We notice that since there is an excess of water, we can directly compute the yielded grams of hydrogen by using the following stoichiometric procedure, considering the 2:1 molar ratio between sodium and hydrogen (notice the 2 before the sodium and the 1 before the hydrogen at the chemical reaction) and that gaseous hydrogen has a molar mass of 2 g/mol:

[tex]m_{H_2}=11.50gNa*\frac{1molNa}{22.98gNa} *\frac{1molH_2}{2.02molNa} *\frac{2gH_2}{1molH_2} \\\\m_{H_2}=0.504gH_2[/tex]

Best regards.

Answer:

0.503g of H₂ are produced

Explanation:

Based on the chemical reaction:

2 Na + 2 H₂O → 2 NaOH + H₂

2 moles of Na react with 2 moles of water to produce 2 moles of NaOH and 1 mole of H₂

11.50g of Na -limiting reactant, molar mass 22.99g/mol- are:

11.50g× (1mol / 22.99g) = 0.500 moles of Na.

As 2 moles of Na produce 1 mole of H₂:

0.500 moles of Na × (1 mole H₂ / 2 moles Na) = 0.250 moles of H₂

As molar mass of H₂ is 2.01g/mol:

0.250 moles of H₂ × (2.01g / 1mol) = 0.503g of H₂ are produced

Which statement describes how a basic coffee cup calorimeter works?
OOO
It measures the mass of a substance given the specific heat and temperature of water in a cup of known size.
It measures the density of a substance given the mass, specific heat, and temperature of water in a cup of known size,
It uses the mass and specific heat of water along with a pressure gauge to measure the gain or loss of energy when a substance is
added.
It uses the mass and specific heat of water along with a thermometer to measure the gain or loss of energy when a substance is
added.

Answers

Answer:

It uses the mass and specific heat of water along with a thermometer to measure the gain or loss of energy when a substance is added.

Explanation:

The calorimeter is an instrumental device, which is used to measure the heat of chemical reactions. The heat is measured when the reactants change their state in specified conditions.

The correct answer is:

Option D. It uses the mass and specific heat of water along with a thermometer to measure the gain or loss of energy when a substance is added.

The coffee cup calorimeter works as:

1. Coffee cup is a type of insulator. The cup of styrofoam with an inserted thermometer can calculate the heat transfer.

2. The thermometer is used to measure the change in the enthalpy of the reaction.

3. The water in the cup absorbs the heat from a reaction, and the cup is adiabatic. Thus, the outer cup is an insulator.

4. The coffee cup measures the specific heat and mass of the water during a chemical change.

Thus, the coffee cup calorimeter uses the heat transfer and mass of the water when a substance is added.

To know more about calorimeter, refer to the following link:

https://brainly.com/question/10987564

Wax is a nonpolar substance . In which type of substance is it the most soluble ?

Answers

Answer:

nonpolar

Explanation:

Use the phrase "like dissolves like"

- Hope that helps! Please let me know if you need further explanation.

What is the concentration of a solution in which 10.0 g of AgNO, is dissolved in 450 mL of solution?
M

Answers

Answer:

M=0.15

Explanation:

138 g AgNO -> 1 mol AgNO

10 g AgNO   -> x

x= (10 g AgNO * 1 mol AgNO)/138 g        x=0.07 mol AgNO

450 mL=0.45 L

M= mol solute/L solution

M= 0.07 mol AgNO/0.45L

M=0.15

Which one is it? Please help

Answers

Chemical properties can only be tested if you change the substance

Answer:

Chemical properties can be tested without changing the substance

Explanation:

Which options identify what the arrows in the diagram
represent? Check all that apply.
D atoms
elements
energy
gas
particles

Answers

Answer:

D

Explanation:

When humans plant more trees, carbon can begin entering the ____
a- hydrosphere
b- geosphere
c- biosphere

Answers

Answer:

biosphere

Explanation:

The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, geosphere, hydrosphere and atmosphere of the Earth.

The biosphere refers to the regions of the surface and atmosphere of the earth or another planet occupied by living organisms.

Plants are responsible for taking in carbon in nature. When more trees are planted, carbon is absorbed by plants which is a component of the biosphere. Hence planting more trees means increasing the intake of carbon into the biosphere.

What is the overall reduction potential for the reaction Agt (aq) + Cu(s)——>Ag(s) + Cu2+ (aq)?
-0.46 V
+0.46 V
+0.57 v
+1.14V

Answers

Answer:

it should be +0.46 :)

Explanation:

I just took the test and got it right.

Answer:

I think it's +1.14 V, but don't take my word for it..

Chloroform is a commonly used anesthetic with a density of 1.483 g/mL. Determine the volume of chloroform needed to deliver a 9.37 g sample of the anesthetic

Answers

Answer:

The correct answer is 6.32 ml

Explanation:

We have the following data:

Mass : m = 9.37 g

Density : d= 1.483 g/mL

The density a substance is equal to the mass of the substance divided into its volume. So, we calculate the volume (V) of chloroform from the mass and density as follows:

[tex]d=\frac{m}{V}[/tex]   ⇒  [tex]V = \frac{m}{d} = \frac{9.37 g}{1.483 g/ml} = 6.32 ml[/tex]

What is the percentage composition of cobalt in cobalt(II) fluoride, CoF2?

Answers

Answer:

60.8%

Explanation:

We'll begin obtaining the molar mass of cobalt(II) fluoride, CoF2. This can be done as shown below:

Molar mass of CoF2 = 59 + (19x2) = 97g/mol.

The percentage composition of cobalt in cobalt(II) fluoride, CoF2 is given by:

Mass of Co/Molar Mass of CoF2 x 100

=> 59/97 x 100 = 60.8%

Therefore, the percentage composition of cobalt in cobalt(II) fluoride, CoF2 is 60.8%

1. How much 6.0 M HNO3 is needed to neutralize 39 mL of 2.0 M KOH?

2. How much 3.0 M NaOH is needed to neutralize 30. mL of 0.75 M H2SO4?

3. What is the concentration of 20 mL of LiOH if it is neutralized by 60 mL of 4 M HCl?

4. What is the concentration of 60 mL of H3PO4 if it is neutralized by 225 mL of 2 M Ba(OH)2?

5.How much 2 M HBr is needed to neutralize 380 mL of 0.1 M NH4OH?

Answers

Answer:

For 2. the answer is 15.0 mL

For other examples, you can solve by exact way as I have solved the 2nd example.

I have writen down all the balanced chemical reaction equation for examples 1, 3, 4, 5 for you. ( picture 2 )

Explanation:

Please see the step-by-step solution in the picture attached below.(picture 1)

Hope this answer can help you. Have a nice day!

Given:
CH4 + 2O2 → CO2 + 2H2O, ΔH = -890 kJ/mol

How much energy is released when 59.7 grams of methane (CH4) reacts with oxygen?

The combustion of 59.7 grams of methane releases ____ kilojoules of energy

Answers

Answer:

The combustion of 59.7 grams of methane releases 3320.81 kilojoules of energy

Explanation:

Given;

CH₄ + 2O₂ → CO₂ + 2H₂O, ΔH = -890 kJ/mol

From the combustion reaction above, it can be observed that;

1 mole of methane (CH₄) released 890 kilojoules of energy.

Now, we convert 59.7 grams of methane to moles

CH₄ = 12 + (1x4) = 16 g/mol

59.7 g of CH₄ [tex]= \frac{59.7}{16} = 3.73125 \ moles[/tex]

1 mole of methane (CH₄) released 890 kilojoules of energy

3.73125 moles of methane (CH₄) will release ?

= 3.73125 moles x  -890 kJ/mol

= -3320.81 kJ

Therefore, the combustion of 59.7 grams of methane releases 3320.81 kilojoules of energy

Answer:

The combustion will release -3,321 KJ/mol of energy

Explanation:

Is the same reactant always the limiting reactant?

Answers

No because the limiting reactant is determined by calculating the amount of product therefore the limiting reactant will not be the same for a given reaction

Why is fusion not used to generate electrical power ?

Answers

Answer:

Fusion doesn't produce runway chain reactions the way fission can, so there's no need to worry about meltdowns.

Way too much energy

How might an antioxidant prevent another element from gaining or losing an electron?

Answers

Answer:

An antioxidant helps in the mopping up and elimination of free radicals and a common example is Glutathione. Oxidation reactions Involves the transfer of electrons or addition of oxygen to a substance.

Antioxidants help in decreasing or prevention of the oxidation of the molecules due to free radicals being formed which causes damage in the cells of animals.

There are 0.55 moles of carbon dioxide gas in a 15.0 L container. This container is at a temperature of 300 K. What is the pressure of the gas inside the container? Use 8.31 L*kPa/mol*K for the gas constant.


A.)760 mm Hg\

B.) 271 kPa

C.) 2 atm

D.) 91.4 kPa

Answers

Answer:

[tex]\large \boxed{\text{D.) 91 kPa}}[/tex]

Explanation:

We can use the Ideal Gas Law — pV = nRT

Data:

V = 15.0 L

n = 0.55 mol

T = 300 K

Calculation:

[tex]\begin{array}{rcl}pV & =& nRT\\p \times \text{15.0 L} & = & \text{0.55 mol} \times \text{8.31 kPa$\cdot$ L$\cdot$K$^{-1}$mol$^{-1}\times$ 300 K}\\15.0p & = & \text{1370 kPa}\\p & = & \textbf{91 kPa}\end{array}\\\text{The pressure in the container is $\large \boxed{\textbf{91 kPa}}$}[/tex]

What is the % of each element in Ni3{PO4) 2 ?​

Answers

Answer:

nickel 48.1063%

Phosphorus 16.9245%

Oxygen 34.9692%

The percent composition of each element like nitrogen, oxygen and phosphorous in Ni₃(PO₄)₂ are 48.03%, 34.97% and 16.93% respectively.

How do we calculate % composition?

Percent composition of any element present in any compound will be calculated as:
% comosition = (Mass of element / Mass of compound)×100%

Mass of Ni₃(PO₄)₂ compound = 366.02 g/mol

Molar mass of 3 Nitrogen atoms = 3×58.6 = 175.8 g/mol

Moar mass of 2 Phosphorous atoms = 2×31 = 62 g/mol

Moar mass of 8 Oxygen atoms = 8×16 = 128 g/mol

% comosition of Nitrogen = (175.8/366.02)×100% = 48.03%

% comosition of Oxygen = (128/366.02)×100% = 34.97%

% comosition of Phosphorous = (62/366.02)×100% = 16.93%

Hence % composition of nitrogen, oxygen and phosphorous is 48.03%, 34.97% and 16.93% respectively.

To know more about percent composition, visit the below link:

https://brainly.com/question/21044245

5) Usted empuja muy fuerte un escritorio pesado e intenta moverlo. Usted efectúa trabajo sobre el escritorio: a.- Ya sea que lo mueva o no, siempre y cuando usted ejerza una fuerza. B.- Sólo si el escritorio se mueve. C.- Sólo si el escritorio no se mueve. D.- Nunca; el escritorio hace trabajo sobre usted. E.- Ninguna de las anteriores. ME AYUDAN PORFA?

Answers

Answer:

5) You push hard on a heavy desk and try to move it. You do work on the desk: A.- Whether you move it or not, as long as you exert a force. B.- Only if the desktop moves. C.- Only if the desktop does not move. D.- Never; the desk does work on you. E.- None of the above. CAN YOU HELP ME?

B.- Only if the desktop moves.

Explanation:

No work is done if a force is exerted but no displacement occurs. A force perpendicular to the displacement does no generate work.

What is the mass of 3.00 moles of carbon

Answers

Answer:

36 grams as 1 mole is 12 grams

Answer:

tbh idk cause I will love to answer your question but ehh

what started the wildfires

Answers

Answer:

It is a typical fires that started out of a lightning strike, or people carelessly starting it, or accidentally, or even arson, that went un-noticed and got out of hand.

Answer:

Explanation:

Forest fires always start by one of two ways - naturally caused or human caused. Natural fires are generally started by lightning, with a very small percentage started by spontaneous combustion of dry fuel such as sawdust and leaves. On the other hand, human-caused fires can be due to any number of reasons.

what does Reproducibility mean? Plz help me

Answers

Answer:

the ability to be reproduced or copied.

Explanation:

Answer:  the ability of an entire experiment or study to be reproduced, either by the researcher or by someone else working independently.

What is the oxidation half-reaction for this unbalanced redox equation? cr2o72– + fe2+ → cr3+ + fe3+ cr3+ → cr2o72– cr2o72– → cr3+ fe3+ → fe2+ fe2+ → fe3+?

Answers

Answer:

6Fe^2+(aq) -------> 6Fe^3+(aq) + 6e

Explanation:

The balanced oxidation half equation is;

6Fe^2+(aq) -------> 6Fe^3+(aq) + 6e

A redox reaction is actually an acronym for oxidation-reducation reaction. Since the both reactions are complementary, there can't be oxidation without reduction and there can't be reduction without oxidation.

The main characteristic of redox reactions is that electrons are transferred in the process. The number of electrons transferred is usually deduced from the balanced reaction equation. For this reaction, the balanced overall reaction equation is;

Cr2O7^2–(aq) + 6Fe^2+(aq) +14H^+(aq)→ 2Cr^3+(aq) + 6Fe^3+ (aq) + 7H2O(l)

It is clear from the equation above that six electrons were transferred. Thus six Fe^2+ ions lost one electron each in the oxidation half equation as shown in the balanced oxidation half equation above.

How many grams of CO2 are produced from the burning of 1.0 mol of amyl alcohol, C5H11OH?

Answers

Answer:

220g of CO2

Explanation:

Step 1:

The balanced equation for the reaction.

2C5H11OH + 15O2 —> 10CO2 + 12H2O

Step 2:

Determination of the number of mole of CO2 produced by burning 1 mole of C5H11OH.

From the balanced equation above,

2 moles of C5H11OH produced 10 moles CO2.

Therefore, 1 mole of C5H11OH will produce = (1 x 10)/2 = 5 moles of CO2.

Therefore, 5 moles of CO2 is produced from the reaction.

Step 3:

Conversion of 5 moles of CO2 to grams.

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Number of mole of CO2 = 5 moles

Mass of CO2 =...?

Mass = mole x molar mass

Mass of CO2 = 5 x 44

Mass of CO2 = 220g.

Therefore, 220g of CO2 were obtained from the reaction.

How many milliliters of 0.2 M NaOH are required to exactly neutralize 40 milliliters of 0.1 M HCl?

A) 10
B) 20
C) 40
D) 80

Answers

Answer:

Option B. 20mL

Explanation:

Step 1:

Data obtained from the question.

Volume of base (Vb) =..?

Molarity of base (Mb) = 0.2M

Volume of acid (Va) = 40mL

Molarity of acid (Ma) = 0.1M

Step 2:

The balanced equation for the reaction.

HCl + NaOH —> NaCl + H2O

From the balanced equation above, the following were obtained:

Mole ratio of the acid (nA) = 1

Mole ratio of the base (nB) = 1

Step 3:

Determination of the volume of base, NaOH needed for the reaction. This is illustrated below:

MaVa/MbVb = nA/nB

0.1 x 40 / 0.2 x Vb = 1

Cross multiply

0.2 x Vb = 0.1 x 40

Divide both side by 0.2

Vb = 0.1 x 40 / 0.2

Vb = 20mL

Therefore, the volume of the base is 20mL.

What mass of water will be collected if 20.0
grams of hydrogen are consumed
2H2+O2--->2H2O
358g
179g
44.7g
Or 89.4g

Answers

Answer: 179 of [tex]H_2O[/tex] will be produced.

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of} H_2=\frac{20.0g}{2.01g/mol}=9.95moles[/tex]

[tex]2H_2+O_2(g)\rightarrow 2H_2O[/tex]

According to stoichiometry :

2 moles of [tex]H_2[/tex] give =  2 moles of [tex]H_2O[/tex]

Thus 9.95 moles of [tex]H_2[/tex] will require=[tex]\frac{2}{2}\times 9.95=9.95moles[/tex]  of [tex]H_2O[/tex]

Mass of [tex]H_2O=moles\times {\text {Molar mass}}=9.95moles\times 18g/mol=179g[/tex]

Thus 179 of [tex]H_2O[/tex] will be produced.

What is the compounds of AICI3 and H+

Answers

Answer:

Aluminium Chloride and Hyrdron, also known as proton/

Explanation:

Balance equation: _NO + _H2O = _NH3 + _O2

Answers

Answer:

4NO + 6H2O = 4NH3 + 5O2

Explanation:

Think about it this way: there are 4N's 4O's and 12H's and 10O's on both sides that's what makes it balanced

Hope this helps :)

How many grams of KF are in 2 liters of a 3.0 M solution of KF

Answers

Answer:

mass ( g ) = 348 g

Explanation:

First you know : M = mole / volume (L)

in question you have the M and V and the formula of SUBSTANCE ( KF )

first you get the number of mole from equation above

so 3 = no of mole / 2

no of mole = 3 × 2 = 6 moles

and the moles equation is no of moles = mass ( g ) / molecular weight ( g/mole )

so you have already calculate the moles and you can know the MW from the Question

Mw of KF = 39 + 19 = 58

so n = mass / MW

so 6 = mass / 58

mass ( g ) = 348 g

GOOD LUCK

Which correctly defines a basic solution? A. [H+] is not present. B. [H+] is equal to [OH−]. C. [H+] is less than [OH−]. D. [H+] is greater than [OH−].

Answers

Answer:  A basic solution is defined as a solution which has more hydroxide (OH-) ions than hydronium ions (H+)

What do half-reactions show?
O
A. They show the oxidatign and reduction halves of a reaction.
B. They show only the electrons that are transferred in a reaction.
C. They show the reactant half and the product half of a reaction.
D. They show the ionic equation and the spectator ions of a reaction.

Answers

Answer: A. They show the oxidation and reduction halves of a reaction.

Explanation:

Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.

For a redox reaction: [tex]A+B^+\rightarrow A^++B[/tex]

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.

oxidation half at anode : [tex]A\rightarrow A^++e^-[/tex]

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

reduction half at cathode:  [tex]B^++e^-\rightarrow B[/tex]

Half-reactions show the oxidation and reduction halves of a reaction. The correct answer is option A.

Oxidation is a chemical reaction that involves the loss of electrons by a molecule, atom, or ion. This process results in an increase in the oxidation state of the species undergoing oxidation.

Half-reactions are used to show the oxidation and reduction half of the reaction separately, which makes it easier to balance the overall reaction and to identify the species that are being oxidized and reduced.

In a half-reaction, the species that is being oxidized loses electrons and is called the reducing agent, while the species that is being reduced gains electrons and is called the oxidizing agent. By balancing the number of electrons transferred in each half-reaction, it is possible to balance the overall redox reaction.

In conclusion, half-reactions are used to show the oxidation and reduction halves of a redox reaction separately. Option A is the correct answer.

Learn more about oxidation here:

https://brainly.com/question/13182308

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