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2 years ago

Which of the following is a physical change?

Chemistry

1 answer:

horrorfan [7]2 years ago

8 0

The awnser i think is c

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How many moles are in 2.5L of 1.75 M Na2CO3

mixas84 [53]

Answer: There are 4.375 moles in 2.5 L of 1.75 M $Na_2CO_3$

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of solution = 1.75 M

Volume of solution = 2.5 L

Putting values in equation , we get:

$1.75M=\frac{\text{Moles of} Na_2CO_3}{2.5L}\\\\\text{Moles of }Na_2CO_3=1.75mol/L\times 2.5L=4.375mol$

6 0

2 years ago

A sample of methane (CH4) has a volume of 25 mL at a pressure of 0.80 atm. What is the volume of the gas at each of the followin

Xelga [282]

Answer:

a. 50ml b.10ml c. 6.097ml d. 190.1 ml

Explanation:

According to Boyle's law

Volume is inversely proportional to pressure at constant temerature

Mathematically

P1V1=P2V2

P1=Initial pressure=0.8atm

V1=Initial volume=25ml

making V2 the subject

at 0.4atm P2=0.4 atm,

V2=25×0.8/0.4

=50ml

at 2 atm V2=25×0.8/2

=10 ml

1mmHg=0.00131579

2500mmHg=3.28 atm

At 3.28 atm,V2=25×0.8/3.28

=6.097 ml

at 80.0 torr

1 torr=0.00131579

80 torr=0.1052 atm

at 0.1048 atm V2=25×0.8/0.1048

=190.1 ml

4 0

2 years ago

A neutral group of atoms joined together by covalent bonds

katrin [286]

A MOLECULE
A molecule is a true representative of a covalent bond.

7 0

2 years ago

Which sub-atomic particle is NOT found at the center of the atom?

Ostrovityanka [42]

All the positive charge of an atom is contained in the nucleus, and originates from the protons. Neutrons are neutrally-charged. Electrons, which are negatively-charged, are located outside of the nucleus.

8 0

3 years ago

Read 2 more answers

A solution was made by dissolving 5.10 mg of hemoglobin in water to give a final volume of 1.00 ml. the osmotic pressure of this

Assoli18 [71]

The molecular weight of hemoglobin can be calculated using osmotic pressure

Osmotic pressure is a colligative property and it depends on molarity as

πV = nRT

where

π = osmotic pressure

V = volume = 1mL = 0.001 L

n = moles

R = gas constant = 0.0821 L atm / mol K

T = temperature = 25°C = 25 + 273 K = 298 K

Putting values we will get value of moles

$moles=\frac{\pi V}{RT}=\frac{0.00195X0.001}{0.0821X298}mol$

we know that

$moles=\frac{mass}{molarmass}$

Therefore

$molarmass=\frac{mass}{moles}=\frac{5.10X10^{-3}g}{7.97X10^{-8}}=6.399X10^{4}g$

5 0

2 years ago