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3 years ago

Which of the following will result in a chemical change?

Chemistry

2 answers:

Alinara [238K]3 years ago

5 0

C burning coal in a furnace

Galina-37 [17]3 years ago

3 0

The answer is C. I just finished the test.

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sebanyak 36 gram glukosa (C6H12O6,M=180 g/mol) dilarutkan dalam 250 gram air.jika diketahui Kb air= 0,52° kg/mol.tentukan titik

likoan [24]

Gr terlarut = 36 gr
Mr terlarut = 180 
gr pelarut = 250 gr 
Kb air = 0,52 °C kg/mol 

Tb larutan = ........? 
--------------------------------------... 
ΔTb = Kb.m.i 
ΔTb = Kb. (gr t / Mr t) . (1000/ gr p) .i 
ΔTb = 0,52 x (36/180) x (1000/250) x 1 
ΔTb = 0,416 °C 

Tb = 100 + ΔTb 
Tb = 100 + 0,416 
Tb = 100,416 °C

4 0

3 years ago

Is homogenised milk a solution, suspension or a colloid?

Wewaii [24]

Answer: Homogenized milk is a colloid mixture.

Explanation: The particle size of homogenized milk is in between a solution which is much bigger but quite smaller enough than suspensions.

4 0

4 years ago

A. Clearly draw the Lewis structure for the PBr4- ion. Show your math where

Nataliya [291]

Answer:

Br-P-Br

Explanation:

To calculate the valance electrons, look at the periodic table to find the valance electrons for each atom and add them together. P is in column 5A, so it has 5, Br is in column 7A, so it has 7 (multiply by 4 since there are 4 Br atoms to give 28) and there is a 1- charge, so add one more electron. 5+28+1=34, so there are 34 electrons to place. P would be the central atom, so place it in the middle. Place each Br around the P (as shown above) with a a single line connecting it. Each line represents 2 electrons, so 8 total have been place, leaving 26 remaining. Place 6 electrons around each Br (2 on each of the unbonded sides), which leaves 2 electrons remaining. The remaining pair of unbound electrons will be attached to the P between any two Br atoms. Phosphorus doesn't have to follow the octet rule, so it actually ends up with 10 valance electrons.

4 0

3 years ago

Read 2 more answers

A 3.0 M HCl(aq) solution contains a total of

Strike441 [17]

It would be answer 3

8 0

3 years ago

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 18.0 g of luminol into a total vol

Paladinen [302]

Answer:

1.36M

Explanation:

Luminol is a compound having the molecular formula as C8H7N3O2.

To know the molarity of the stock solution of Luminol, we shall carry out the following:

Step 1:

we shall calculate the number of mole in 18g of luminol. This is shown below:

Molar mass of C8H7N3O2 = (12x8) + (7x1 ) + (14x3) + (16x2)

= 96 + 7 + 42 + 32

= 177g/mol

Mass of C8H7N3O2 = 18g

Number of mole of C8H7N3O2 =..?

Mole = Mass /Molar Mass

Number of mole of C8H7N3O2 = 18/177 = 0.102 mole.

Step 2:

Conversion of 75.0 mL of H2O to Litre (L).

1000mL = 1L

Therefore, 75mL = 75/1000 = 0.075L

Step 3:

Determination of the molarity of the stock solution of Luminol.

Molarity is simply defined as the mole of solute per unit litre of water. Mathematically, it is represented as:

Molarity = mole /Volume

With the above formula, we can obtain the molarity of the stock solution of Luminol as follow:

Mole of C8H7N3O2 = 0.102 mole

Volume of water = 0.075L

Molarity =..?

Molarity = mole /Volume

Molarity = 0.102/0.075

Molarity = 1.36M

Therefore, the molarity of the stock solution of Luminol is 1.36M.

3 0

3 years ago