Which evidence shows that heat is given off when a candle burns?
A. A match is used to light the candle.
B. The burning candle produces a yellow flame.
O c. Covering the burning candle extinguishes the flame.
D. Solid candle wax near the flame melts as the candle burns.
thing

Answer:

You need to make sure the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. In order make both sides equal, you will need to multiply the number of atoms in each element until both sides are equal. :)

Answer:

I believe Gases A and D

Explanation:

The lines in both gases match up with the lines in the unknown mixture.

Answer:

Fa (rt) and Nitrogen

Explanation:

Answer:

a. forces acting on the object

Answer:

A Watershed

Explanation:

A watershed consists of all the land that supplies water to a river system

Answer:

watershed

Explanation:

Answer: Option (b) is the correct answer.

Explanation:

When thermal energy is added to a substance then there will occur an increase in the kinetic energy of molecules. As a result, motion of particles increases due to which a solid substance changes into liquid state and a liquid substance changes into gaseous state.

When a liquid substance gets converted into vapors or gaseous state then this process is called vaporization.

Thus, phase changes that requires the addition of thermal energy is vaporization.

Answer: [tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\textrm{He}[/tex]

Explanation:

Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.

General representation of an element is given as:   [tex]_Z^A\textrm{X}[/tex]

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

General representation of alpha decay :

[tex]_Z^A\textrm{Sr}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]

The  balanced nuclear equation when the isotope Strontium-90 decays by Q-  decay is :

[tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\textrm{He}[/tex]

Explanation:

The neutral aluminium atom loses all 3 of its valence electrons to obtain a stable octet structure.

The aluminium ion has a positive charge of 3.

=> Al3+, Charge = +3.

Answer:

It would be false because there are series circuit that only has one path

Answer A. The electronegativity of one atom is less than 1.7

Answer: its C

Explanation: i just got it wrong the right answer is c

Answer:

Molecular Formulas for Compounds

Explanation:

Hope my answer helps you.

Answer:

double

Explanation:

.

Answer:

A

Explanation:

Answer:

dic

Explanation:

Answer: these are for questions 1,2,4,5,7

Explanation: number 3: as the pressure in the volume decreases, the volume increases causing it to expand and eventually blow.

number 6: because the temperature and the amount of gas don’t change, these terms don’t appear in the equation. What Boyle’s law means is that the volume of a mass of gas is inversely proportional to its pressure. This linear relationship between pressure and volume means doubling the volume of a given mass of gas decreases its pressure by half.

hope this helps :))

Answer: Option (b) is the correct answer.

Explanation:

It is known that,

                   pH + pOH = 14

So, pOH = 14 - pH

As the given pH is 9.3. Hence, pOH for the given solution will be calculated as follows.

          pOH = 14 - 9.3

                   = 4.7

Therefore, pOH of the given solution is 4.7.

Answer:

1.389

Explanation:

P = m / V

m = 1250

V = 4x9x25 = 900

1250/900 = 1.388889

Answer:

in sixth period out of 32 elements, 14 elements have been placed separately in horizontal row below periodic table.

Answer:

When moving from left to the right of a period, the number of electrons increases and the strength of shielding increases. As you move across period the number of shells remain same, the shielding effect will also remain constant.

Explanation:

Answer:

hydrogen oxygen carbon and nitrogen

Answer:

1. A. 0

2. B. 7

3. C. 4

Explanation:

1. charge is equal to the number of protons minus the number of electrons!

2. neutrons is equal to mass number minus atomic number!

3. valence electrons equal 4!

Hope this helped you! :)

Answer:

1813.74g

Explanation:

Given parameters:

Number of moles of radon  = 8.17moles

Unknown:

Mass of radon  = ?

Solution:

To solve this problem, we use the expression below:

      Number of moles = [tex]\frac{mass}{molar mass}[/tex]  

Molar mass of radon  = 222g/mol

Now insert the parameters and solve;

    Mass of radon  = Number of moles x molar mass

                              = 8.17 x 222

                              = 1813.74g

The abundance of isotope 35 = 75%

The abundance of isotope 37 = 25%

Ratio isotope 35 :  isotope 37 = 3 : 1

Given

Ar Cl = 35.5

Two isotopes of mass number 35 and 37

Required

The ratio of each isotope

Solution

If the abundance of isotope 35 is x%, then the abundance of isotope 37 is (100-x)%

35.5 = x%.35 + (100-x)%.37

35.5 = 0.35x+0.37(100-x)

35.5=0.35x-0.37x+37

0.02x=1.5

x=75

A fuel cell require a continuous input of fuel and an oxidizing agent in order to sustain the reactions which generate the electricity. The item in which  fuel cells more commonly used is propane lanterns. The correct option is D.

The propane lanterns is one of the gas interns which is a lightweight portable device which supplies bright efficient light while protecting its contents from wind and brain. The gas interns are incandescent lights.

The gas interns burn fuel like propane, white gas or kerosene to generate heat and the heat causes the mantles to produce light. The mantles are defined as the ceramic mesh which encase the flame produced by the lantern.

The gas lanterns are very simple, any heated material will produce light. The lantern burns fuel to produce heat. The gas lanterns use mantles instead of limestone blocks. The mantles are highly efficient at producing light from the heat they acquire.

Thus the correct option is D.

To know more about fuel cell, visit;

https://brainly.com/question/28329395

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Moles of Ammonia (NH₃) in solution = 1.14

Given

0.175 L of 6.50 M aqueous ammonia

Required

moles of ammonia

Solution

Ammonia = NH₃

Molarity = moles of solute per liter of solution

[tex]\tt M=\dfrac{n}{V}[/tex]

n = M x V

n = 6.50 M x 0.175 L

n = 1.1375 moles

In a multiplication operation: the significant digits in the final product must follow the number of significant digits that are at least in the numbers involved in multiplying

6.50 = 3 sig fig

0.175 = 3 sig fig

So the result must be 3 sig fig

1.1375 rounded to 1.14

Answer:

Sublimation is a physical change. When a substance sublimes, it changes from a solid to a gas without going through the liquid phase.

Explanation:

Answer:

covalent

Explanation: