3.
What are valence electrons? How do you quickly determine the number of valence electrons an
atom has?

Answer:

Option C. Change in enthalphy is negative, the reaction is exothermic.

Explanation:

In the profile diagram given in the question above, we can see clearly that the energy of the reactant (Hr) is higher than the energy of product (Hp).

Hence, the enthalpy change (ΔH) will be negative i.e

Enthalpy change (ΔH) = Energy of product (Hp) – Energy of reactant (Hr)

ΔH = Hp – Hr = negative (–) [since Hr is higher than Hp]

A reaction in which the enthalpy change (ΔH) is negative is termed exothermic reaction.

Answer:

the element is lead

Explanation:

the atomic number of lead is 82.

number of protons 82

number of electrons 82

Explanation:

16 A. 17C matter 18C molecule 19D wavelength 20 C deposition

Answer:

I think As is larger

Explanation:

Answer:

D ≈ 4.86 g/mL

Explanation:

Density = Mass over Volume

D = m/V

Step 1: Define variables

m = 13.76 g

V = 2.83 mL

D = unknown

Step 2: Substitute and Evaluate for Density

D = 13.76 g/2.83 mL

D = 4.8621908127208480565371024734982 g/mL

Step 3: Simplify

We are given 3 sig figs.

4.8621908127208480565371024734982 g/mL ≈ 4.86 g/mL

Answer:

Sum of both value is  101.63 km

Explanation:

Given data:

1st value = 92.2 km

2nd value = 9426 m

Sum of both value in km = ?

Solution:

We know that there are 1000 m in 1 km. Thus,

   92.2 km + 9426 m/1000 m × 1 km   = 101.63 km

Thus, sum of both value is  101.63 km

Answer:

The number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products.

The statement best describes balancing equations and the law of conservation of mass is the number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products. Therefore, option B is correct.

According to the law of conservation of mass or principle of mass conservation, any system that is closed to all transfers of matter and energy must maintain a constant mass over time since the system's mass cannot vary and neither more nor less amount can be added or subtracted.

This law states that no matter what physical or chemical change occurs, the overall mass of the products and reactants remain identical.

Understanding and producing different chemical reactions depend heavily on this law. Researchers might anticipate how much the result would be if they knew the identities and quantities of the reactants for each reaction.

Thus, option B is correct.

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C or D i think maybe

Answer:

D and A

Explanation:

Answer:

Partial pressure of Gas A = 3.91 atm

Partial pressure of Gas B = 5.10 atm

Partial pressure of Gas C = 5.99 atm

Explanation:

Number of moles of gas A;

n_A = 13.56 g/mol ÷ 6 g = 2.25 moles

Number of moles of gas B;

n_B = 11.76 g/mol ÷ 4 g

n_B = 2.94 moles

Number of moles of gas C;

n_C = 12.07 g/mole ÷ 3.5 moles

n_C = 3.45 moles

Total number of moles = n_A + n_B + n_C = 2.25 + 2.94 + 3.45 = 8.64 moles

Mole fraction of gas A; X_a = 2.25/8.64

Mole fraction of gas B;X_b = 2.94/8.64

Mole fraction of gas C;X_c = 3.45/8.64

Now, partial pressure of each gas will be;

Mole fraction × Total pressure

We are given total pressure of 15 atm.

Thus;

P_a = (2.25/8.64) × 15

P_a = 3.91 atm

P_b = (2.94/8.64) × 15

P_b = 5.10 atm

P_c = (3.45/8.64) × 15

P_c = 5.99 atm

Thus;

Partial pressure of Gas A = 3.91 atm

Partial pressure of Gas B = 5.10 atm

Partial pressure of Gas C = 5.99 atm

Answer:

AR(18)  

Explanation:

Try that it should work

                                                                                                                                         *(

Answer: Two nonmetals.

Explanation:

Answer:The only pair of nonmetals is sulfur and fluorine.

Explanation:The pair of elements most likely to form a molecular compound with each other are two nonmetals.

Answer:

b

Explanation:

Answer:

The answer  is  [tex]\frac{dT}{dP} = 2.84*10^{-4}\ K/Pa[/tex]

Explanation:

From the question we are told that

  The boiling point of water is  [tex]T_b = 100^oC = 100 + 273 = 373 \ K[/tex]

  The enthalpy of vaporization is  [tex]\Delta H_{vap} = 40.69 \ kJ mol-1 = 40.69 *10^{3} \ J/mol[/tex]

  The molar volume of liquid water is  [tex]V =0.019 * 10^{-3} m^3 mol^{-1}[/tex]

   The molar volume of steam is  [tex]V_s = 30.199 * 10^{-3} \cddot m^3\cdot mol^{-1}[/tex]

  The pressure is  [tex]P = 1.01325 \ bar[/tex]

Gnerally from Clausius Clapeyron equation we have that

      [tex]\frac{dP}{dT} = \frac{\Delta H_{vap}}{ T * \Delta V}[/tex]

Here  [tex]\Delta V = V_s - V[/tex]

=>     [tex]\Delta V = [30.199 * 10^{-3} ] - [ 0.019 * 10^{-3}][/tex]

=>     [tex]\Delta V = [30.199 * 10^{-3} ] - [ 0.019 * 10^{-3}][/tex]      

=>     [tex]\Delta V = 0.03018 \ m^3 mol^{-1}[/tex]          

So

    [tex]\frac{dP}{dT} = \frac{40.69 *10^{3} }{ 373 * 0.03018}[/tex]

=>  [tex]\frac{dP}{dT} = 3522.28 \ Pa/K[/tex]

Generally from the we are ask to obtain the change in the boiling point of water at 1000 C per Pa change under atmospheric pressure conditions which is mathematically represented as

       [tex]\frac{d T}{dP}[/tex]

So

    [tex]\frac{dT}{dP} = \frac{1}{\frac{dP}{dT} } = \frac{1}{3522.28}[/tex]

=> [tex]\frac{dT}{dP} = \frac{1}{\frac{dP}{dT} } = 2.84*10^{-4}\ K/Pa[/tex]

Answer:

Chemical

Explanation:

physical, because chemicl would be if it was disolving with water

Answer:

frogs don't spend all their time swimming, nor do they spend all ... The frog is capable of sitting perfectly still for hours on end, only to suddenly ... When a frog is resting or hunting, he will sit on whatever is handy.

Explanation:

Hope I helped if I did please mark me brainiest Thanks! <333 :3

Answer:

Explanation:

I hope this helps

Answer:

A: They bring cool air.

Explanation:

Took the test and got it correct. :)

Jet streams are fast flowing meandering air currents. Polar jet streams bring cool air through the atmosphere. Polar jets meet subtropical jets at some regions.

The polar jet stream, which travels through the lower layers of the atmosphere in the Northern Hemisphere, is a swiftly moving band of westerly winds.

The confluence of warm air ascending from the tropics and cold air masses descending from the arctic produces the jet. The denser cold air lowers and deflects the warmer air areas north, creating deep troughs and steep ridges that give the jet stream its wavy appearance.

As pockets of cold air intermittently sneak down from the Arctic, this pattern spreads across the mid-latitudes of North America, Europe, and Asia, producing opposing waves and flows that speed eastward due to the earth's rotation.

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Answer:

The correct answer is C. None of the above.

Explanation:

To determine how long the black bear will run, the distance it will travel must first be determined. Thus, the proposed calculation must be solved.

1.95 x 10 ^ 4

1.95 x 10 x 10 x 10 x 10

19.5 x 10 x 10 x 10

195 x 10 x 10

1950 x 10

19500

Thus, the bear will run 19,500 miles, so, running at 35 mph, it will take about 557 hours to run that distance (19,500 / 35).

Answer:

Explanation:

Oxyacids are acid containing oxygen; they are also known as acid-alcohol or acid-phenol. As said earlier, the strength of these acids increases with increases in the polarity of these compounds. So, what makes the polarity is as a result of the electronegative substituents attached to it. Halogen family possesses the highest electronegativity in the periodic table, and electronegativity decreases down the group.

The ranking of the oxyacids in order of decreasing acid strength from strongest to weakest acid is:

HClO3 > . HClO2 > HClO > HBrO

Answer:

Salt is effective as a preservative because it reduces the water activity of foods. .

Answer:

ans. will be a. an alcohol

1. This experiment was to find how mass and speed effect KE. This is important because if you were in a situation where you needed something to go higher, you would know to add more or less of mass/speed.  

To test mass, we filled the bean bag with a certain amount of water, then dropped it. After, you recorded how high it made the bean bag go. The same with speed, but same amount in the bottle, just dropped from different heights.  

My hypothesis is when you have more mass, the KE will be greater. This is also the same with speed, if it is dropped from a higher place, the bean bag will launch farther than the last time.  

2. Data I collected from the lab was like my hypothesis explained. When the height of the bottle increased, it made the bean bag go higher than the last. And I tested 4 different masses, 0.125 kg, 0.250kg, 0.375kg and 0.500kg. Each time the bean bag went higher on a larger mass.  

A lot of times on the speed test, the bean bag would go higher than the bottle drop point, but not every time. Also, when it was dropped from the same height each time, some results varied quite a bit, like when it was dropped from 1.28 the results were 1.14 then 1.30 1.30. Mass on the other hand was all in the same number range, only once the numbers were a bit off from each other.  

3.  Some formulas I used were KE= ½ mv^2 and Ht v^2/2g. The first was to calculate the kinetic energy of an object, m=mass v=speed. Second was for finding out what height I needed to drop something to reach a certain speed, Ht=Height and g= Gravitational Acceleration of 9.8 m/s^2.  

I used these to figure out tables that showed relationships between different things like mass and KE or speed and height. The whole time I was doing the lab, my data was going up, when there was more mass/speed there were higher values in the table.  

This means that my hypothesis at the beginning was correct, more of m/s means KE will increase proportionally because they are all linear. I found it surprising when the bean bag height went over the water bottle drop mark.  

4.     To conclude, my hypothesis matched my data. The data values went up when more mass or speed was added. This means if I were in a situation where I needed more kinetic energy for something, I would know to increase mass or the speed of the object giving it energy.  

The reason that this hypothesis is correct is when you have more mass, you have more energy. So, when you drop let's say a baseball, it isn’t that heavy so it would only launch the bean bag so far. But a bowling ball is very heavy and has lots of energy when falling because of that, it would make the bean bag go very high.  

To make this experiment better, I would use a smoother material for the lever so energy wouldn’t be lost by friction from wood rubbing together. Also, maybe a scanner or video camera to more accurately record how far the bean bag went. All of these would help the lab get more precise results, maybe they could be used in a future lab.

Explanation:

Answer:

ima give my whole doc if anyone need it in future like i did Edge 2023

Explanation:

Answer:

their are many alternative for cornstarch.But I know only 10 of them and they are:

1.Rice Flour

2.wheat Flour

3.Potato Starch

4.Arrowroot

5.Tapioca

6.Ground Flaxseeds

7.Gaur Gum

8.Xanthan Gum

9.Glucomannan

10.Xanthan Gum

Answer:

B. 3.0 g/ml

Explanation:

density formula: mass/volume

15/5=3

Answer: The answer is blue, white, yellow-white, orange.

Explanation: These are the two basic reasons for different star colors:

Temperature – cooler stars are red, warmer ones are orange through yellow and white. The hottest stars shine with blue light

Age – As a star ages it produces different chemicals which burn at different temperatures. We can use a star’s color to show its relative age

Answer:

OR D

Explanation:

D on edge 2020

Answer:

c. stays the same, changes

Explanation:

temperature and heat go hand in hand, however while the change of state occurs, the temperature remains the same while the heat increases since the heat input is constant.

As a change of state takes place, heat and temperature: C. stays the same, changes.

Matter can be defined as anything that has mass and occupies space. Thus, any physical object or substance that is found on earth is typically composed of matter.

Since all matter are made up of atoms, they have a property of existing in three (3) distinct states and these include;

Generally, matter changes state when heat (thermal energy) is released or absorbed with a corresponding change in its temperature.

In conclusion, at the point when the change of state is taking place, heat stays the same and temperature changes.

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Answer:

The correct option is acetic acid

Explanation:

Distillation is the process of separating a mixture of substances based on differences in boiling points. During distillation, the compound with the lowest/least boiling point is distilled and collected first and then the one with the next least boiling point and it goes on like that.

From the explanation above, acetic acid has the least boiling point (in the organic layer) with 118°C and thus will distill first. This is then followed by isopentyl alcohol (130°C) and then isopentyl acetate (142°C) and finally sulfuric acid water (290°C).

Answer:

Q = 65 kJ

Explanation:

Given that,

Mass, m = 580 g

Initial temperature, [tex]T_i=25^{\circ} C[/tex]

Final temperature, [tex]T_f=150^{\circ} C[/tex]

The specific heat capacity for aluminum is 0.897 J/g°C

We need to find the heat added to the aluminium pan so that its heat raised to a temperature from 25°C to 150°C. It is given by :

[tex]Q=mc\Delta T\\\\Q=580\ g\times 0.897\ J/g^{\circ} C\times (150-25)^{\circ} C\\\\Q=65032.5\ J[/tex]

or

Q = 65.03 kJ

or

Q = 65 kJ

Hence, the heat added to the pan is 65 kJ.

Answer:

question 1 answer is b

Explanation:

istopes equal to same atomic number but different mass number