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Answer:

9.1093837015 × 10^−31 kg

Very small mass

Answer:

ans:Ne=2,8,1

ans:2,8,7

Answer:

Freezing water and cracking limestone are physical changes.

Answer:

C. the amount of drug x given to mice

Answer:

81 °C

Explanation:

This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:

q = heat added/released by a sample

m = mass of sample

c=specific heat of sample

ΔT = change in temperature

from here we can rearrange the equation to state:

q/(mc) = ΔT

1200J/((20.0g)(4.2J/g•°C)) = ΔT

14°C = ΔT

If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.

Answer:

C. 81 c

Explanation:

took the test :)

Answer:

A. The product formed have more energy than the reactants.

This is because it is an endothermic reaction.

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Answer:A force is a push or pull upon an object resulting from the object's interaction with another object.

A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate

Answer:

the answer is the number of gas molecules changes.

Answer:

It would take sound 104.998 seconds to travel across lake tahoe.

Explanation:

First let's convert the miles to meters, so, 21.6 miles = 34754.4 meters

Now, we will divide this number in meters by 331. So, 34754.4 / 331 = 104.998

And what will the unit be? Seconds will be the unit for time here so 104.998 seconds.

Explanation:

No, that would be incorrect

Answer:

There arre two main parts of the atom, the nucleus and the orbital rings. The three subatomic particles are contained in each of these, the proton and neutron together in the nucleus and the electrons orbiting in the rings.

Answer: A is correct. I don't see the "element shown below," but it isn't needed to answer this question.

Explanation: By definition, the atomic mass is based on the sum of protons (1 AMU each) and neutrons (1 AMU each). Electrons are assigned a value of 0 AMU.

Answer:

7 gallons

Explanation:

Just do the math

$21 x 1 gallon/$3 =7 gallon

Answer:

reaction of phosphorus with the helegones

Answer:

All right. So let's calculate the density of a glass marble. Remember that the formula for density is mass over volume. So if I know that the masses 18.5 g. And I know that the um volume is 6.45 cubic centimeters. I can go ahead and answer this to three significant figures. So it's going to be 2.87 grams per cubic centimeter. Okay, that's our density. Now, density is an intensive process. Okay. We're an intensive property. I really should say. It doesn't depend on how much you have. Mhm. If I have one marble, its density is going to be 2.87 g per cubic centimeter. If I have two marbles, the density will be the same because I'll double the mass and I'll also double the volume. So when I divide them I'll get the same number. Okay, that's what makes it an intensive property. No matter how many marbles I have, they'll have the same density. Mass though is not an intensive property. So if I have six marbles and I want to know what the massive six marbles is. Well, I know the mass of each marble is 18.5 g. So the mass of six marbles Is going to be 100 11 g. Because mass is an extensive property. It depends on how much you have. If I change the number of marbles, I'm going to change the mass. That's an extensive property. All right. So we've calculated the density. We've calculated the mass and then what happens to the density of one marble compared to six marbles as we mentioned before. Since densities and intensive property, the densities will be the same, no matter how may.

Explanation:

H=hydrogen,H2=hydrogen atoms,

Answer:

jrikgni

Explanation:j

55

Answer:

Nucleus is known as the brain of the cell.

correct option is B letter

Answer:  The combustion of methane (CH4) with O2.

Explanation:  This is a chemical reaction involving carbon:

 CH4 + 2O2 = CO2 + 2H2O

Answer:

» Reactivity and color

Explanation:

though color is very minor answer because it also relates to a physical property.

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Answer:  1.8x10^-4 M H+

Explanation:  The number of moles of NaOH added to the 100 ml soultion will be equal to the number of moles of H+ present in that solution.  

Moles NaOH in 7.2 ml of 2.5x10^-3 M NaOH

(2.5x10^-3 M NaOH) is the same as 2.5x10^-3 moles NaOH/liter

(2.5x10^-3 moles NaOH/liter)*(7.2 ml)*(1 liter/1000ml) = 1.8x10^-4 moles NaOH used to titrate 100 ml of the acid.  That means there was 1.8x10^-4 moles of H^+ in 100 ml.  

Concentration of H^+ = (1.8x10^-4 moles H)/0.100 l) = 1.8x10^-4 M H+

(pH of 3.74)

Answer:

the answer to this problem is a

Answer:

endothermic reaction

Explanation:

because salt dissolve water

Answer:

EXOTHERMIC REACTION AS WHEN YOU TOUCH IT YOU WILL FEEL SOME HEAT.

Answer:

Thanks!!!

Explanation:

Answer:

true

Explanation:

Answer:

solutions is a homogenous mixture while colloids and suspensions are heterogeneous mixtures made up of 3 or more substances

Explanation:

homogeneous- made up of one thing

heterogeneous- made up of 2 or more things

Answer:

D. all of the elements of Group 18 in orange boxes

Answer:

D)driying of limonite these is the answer

In an experiment, we can define 3 types of variables.

Independent variables: Are these ones that the scientist can control and modify, in this case, would be the kind of rubber for the tires.

Dependent variables: Are the variables that react to the changes in the independent variables. In this case, would be "how much lasts each type of rubber".

Controlled variables: Are all of these variables that also have an impact on the dependent variable, so we need to control them (fix them) so they do not affect the study of the independent variable.

So, for this particular experiment, to find controlled variables we need to think on what things do affect the durability of tires.

Some examples can be:

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Answer:

C

Explanation:

alkali metals are the Group I elements, which have 1 electron in their valence shells

Answer:

Alkali metals are the elements which have only one valence electron in their outermost or ultimate shell.

Explanation:

Alkaline Earth metals have 2 valence electron in their outermost shell and readily give up their 2 electron to achieve stability.

Rare Earth Metals have 3 valence electron in their outermost shell and they have high magnetic moments and divert range of magnetic structure.

Alkali Earth metals have 1 valence electron.

Transition metals generally have 2 valence electron .

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Answer:

big ablsolty long pp

Explanation:

dong

Answer: 37 protons, 48 neutrons, and 36 electrons.

Explanation: I assume "Revision" is Rubidium. It is atomic number 37, so it has 37 protons. It's atomic mass is 85, so it has an average of (85-37) = 48 neutrons. It has a charge of +1, so one electron of the original 37 has left.