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PSYCHO15rus [73]
3 years ago
13

I NEED HELP PLEASE!!!!!

Chemistry
2 answers:
lisov135 [29]3 years ago
7 0
Atoms can be divided more so thats not true. atoms from the same element arent all nesacarly identical because of isotopes
jolli1 [7]3 years ago
5 0
Atoms of different elements can combine physically and chemically. 
Chemical reactions occur when atoms are joined or separated.
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You apply the same amount of heat to five grams of water and five grams of aluminum. The temperature of the aluminum increases m
Mashutka [201]
Specific heat is another physical property of matter. All matter has a temperature associated with it. The temperature of matter is a direct measure of the motion of the molecules: The greater the motion the higher the temperature:



Motion requires energy: The more energy matter has the higher temperature it will also have. Typicall this energy is supplied by heat. Heat loss or gain by matter is equivalent energy loss or gain.

With the observation above understood we con now ask the following question: by how much will the temperature of an object increase or decrease by the gain or loss of heat energy? The answer is given by the specific heat (S) of the object. The specific heat of an object is defined in the following way: Take an object of mass m, put in x amount of heat and carefully note the temperature rise, then S is given by



In this definition mass is usually in either grams or kilograms and temperatture is either in kelvin or degres Celcius. Note that the specific heat is "per unit mass". Thus, the specific heat of a gallon of milk is equal to the specific heat of a quart of milk. A related quantity is called the heat capacity (C). of an object. The relation between S and C is C = (mass of obect) x (specific heat of object). A table of some common specific heats and heat capacities is given below:

Some common specific heats and heat capacities: Substance S (J/g 0C) C (J/0C) for 100 g Air 1.01 101 Aluminum 0.902 90.2 Copper 0.385 38.5 Gold 0.129 12.9 Iron 0.450 45.0 Mercury 0.140 14.0 NaCl 0.864 86.4 Ice 2..03 203 Water 4.179 417.9   

Consider the specific heat of copper , 0.385 J/g 0C. What this means is that it takes 0.385 Joules of heat to raise 1 gram of copper 1 degree celcius. Thus, if we take 1 gram of copper at 25 0C and add 1 Joule of heat to it, we will find that the temperature of the copper will have risen to 26 0C. We can then ask: How much heat wil it take to raise by 1 0C 2g of copper?. Clearly the answer is 0.385 J for each gram or 2x0.385 J = 0.770 J. What about a pound of copper? A simple way of dealing with different masses of matter is to dtermine the heat capacity C as defined above. Note that C depends upon the size of the object as opposed to S that does not.

We are not in position to do some calculations with S and C.

Example 1: How much energy does it take to raise the temperature of 50 g of copper by 10 0C?



Example 2: If we add 30 J of heat to 10 g of aluminum, by how much will its temperature increase?

 



Thus, if the initial temperture of the aluminum was 20 0C then after the heat is added the temperature will be 28.3 0C.
5 0
3 years ago
For the reaction represented by the equation cl2 + 2kbr ® 2kcl + br2, calculate the percentage yield if 200. g of chlorine react
alexgriva [62]
The  %  yield if 200g   of chlorine  react  with  excess Potassium bromide to  produce  410g of  bromine  is calculated as below

%  yield =  actual  yield/theoretical yield  x100
the  actual yield = 410 grams

calculate the  theoretical yield
by first  calculate the moles of chlorine used

mole=  mass/molar  mass
molar  mass of Cl2 =  35.5 x2= 71 g/mol

moles=  200g/71g/mol  = 2.82  moles

cl2 +2 KBr = 2KCl  +Br2

by use  of mole ratio between Cl2  to Br2  which is 1:1  the  moles of  Br2 is also = 2.82  moles

theoretical  mass =  moles x molar mass
molar mass of Br2= 79.9 x2= 159.8 g/mol

moles= 2.82g x 159.8 g/mol = 450.64 grams

% yield is therefore = 410g/450.64 x100 = 90.98 %


5 0
3 years ago
1. Consider the following: h2so4 2 naoh → na2so4 2 h2o if a 24. 0 ml sample of h2so4 (aq) was neutralized by 20. 0 ml of 0. 125
jasenka [17]

The molarity of the acid sample H₂SO₄ is 0.052M .

<h3>What is Molarity ?</h3>

Molarity (M) is the amount of a substance in a certain volume of solution.

Molarity is defined as the moles of a solute per liters of a solution.

Molarity is also known as the molar concentration of a solution

Now to determine the molarity of the acid sample

V( H₂SO₄) = 24.0 mL in liters = 24.0 / 1000 = 0.024 L

M(H₂SO₄) = ?

V(NaOH) = 20.0 mL = 20.0 / 1000 = 0.02 L

M(NaOH) = 0.125 M

Number of moles NaOH :

n = M x V

n = 0.125 x  0.02

n = 0.0025 moles of NaOH

H₂SO₄(aq) + 2 NaOH(aq) = Na₂SO₄(aq) + 2 H₂O(l)

1 mole H₂SO₄ ---------- 2 mole NaOH

? mole H₂SO₄ ---------- 0.0025 moles NaOH

moles = 0.0025 * 1 / 2

= 0.00125 moles of H₂SO₄

M(H₂SO₄) = n / V

M = 0.00125 /  0.024

= 0.052 M

Therefore the molarity of the acid sample H₂SO₄ is 0.052M .

To know more about molarity

brainly.com/question/12127540

#SPJ4

8 0
3 years ago
Can someone help me with this I've been stuck on it for a few days​
Fiesta28 [93]
So I haven’t got time to answer all of it for you but the id you look at the picture of the periodic table I’ve added the top number in the red boxes are the groups and the period is how many elements down from the top it is (remember that the hydrogen and helium make up period ONE) so remember to include them when counting the elements as you go down the table

5 0
3 years ago
PLZ ANSWER QUICKLY! The electronegativity values of carbon, hydrogen, and nitrogen are compared in the table. Comparison of Elec
andriy [413]

Answer:

c. CH4 < NH3 because the NH bond is more polar than the CH bond.

Explanation:

Actually, the electronegativity difference between carbon and hydrogen is just about 0.4. This meager difference in electronegativity corresponds to a nonpolar bond between the two atoms.

However, the electronegativity difference between nitrogen and hydrogen is about 0.9. This larger electronegativity difference corresponds to the existence of a polar covalent bond between the two atoms.

Hence the N-H bond is significantly polar unlike the C-H bond. This implies that CH4 molecules are only held together by weak dispersion forces while NH3 molecules are held together by stronger dipole-dipole interactions and hydrogen bonds.

8 0
3 years ago
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