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3 years ago

What do physical changes do?

Chemistry

2 answers:

Citrus2011 [14]3 years ago

6 0

Answer:

Explanation:

A physical change is a change like a piece of paper its still paper. But if you burn the paper it turns into ash. A chemical change changes its chemical state.

Cloud [144]3 years ago

3 0

Answer:d

Explanation: I just took the test

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When 23.6 mL of 0.500 M H2SO4 is added to 23.6 mL of 1.00 M KOH in a coffee-cup calorimeter at 23.50°C, the temperature rises to

hichkok12 [17]

Answer:

-112 Kj/mole (diprotic acid)

Explanation:

6 0

3 years ago

According to the following reaction, how many grams of chloric acid (HClO3) are produced in the complete reaction of 31.6 grams

gogolik [260]

Answer:

$m_{HClO_3}=12.7gHClO_3$

Explanation:

Hello,

Considering the reaction:

$3Cl_2(g)+3H_2O(l)-->5HCl+HClO_3$

The molar masses of chlorine and chloric acid are:

$M_{Cl_2}=35.45*2=70.9g/mol\\M_{HClO_3}=1+35.45+16*3=84.45g/mol$

Now, we develop the stoichiometric relationship to find the mass of chloric acid, considering the molar ratio 3:1 between chlorine and chloric acid, as follows:

$m_{HClO_3}=31.6gCl_2*\frac{1molCl_2}{70.9gCl_2} *\frac{1molHClO_3}{3mol Cl_2} *\frac{85.45g HClO_3}{1mol HClO_3} \\m_{HClO_3}=12.7gHClO_3$

Best regards.

4 0

4 years ago

List all possible oxidation numbers for the elements. 21. Al

Alex73 [517]

Answer:

21. Al (Aluminium)

+3 (most common), -1, -2, +1, +2

22. Bi (Bismuth)

+3 (most common), -3, -2, -1, +1, +2, +4, +5

23. Ni (Nickel)

+2 (most common), -2, -1, 0,+1, +3, +4

24. Xe (Xenon)

0 (most common), +1, +2, +4, +6, +8

25. Pb (Lead)

+2 (most common), +4 (most common), -4, -2, -1, +1, +3

Explanation:

Now we proceed to present the answers for each element:

21. Al (Aluminium)

+3 (most common), -1, -2, +1, +2

22. Bi (Bismuth)

+3 (most common), -3, -2, -1, +1, +2, +4, +5

23. Ni (Nickel)

+2 (most common), -2, -1, 0,+1, +3, +4

24. Xe (Xenon)

0 (most common), +1, +2, +4, +6, +8

25. Pb (Lead)

+2 (most common), +4 (most common), -4, -2, -1, +1, +3

7 0

3 years ago

What are 3 methods you can use to separate a mixture? Give an example of each.

max2010maxim [7]

Answer:

The three methods we can use to separate a mixture are:

1.sublimation

example: sand and camphor

2.centrifugation

example:cream from milk

3.evaporation

example:salt from sea water

6 0

3 years ago

A sample of cobalt has a mass of 27 g and a density of 9 g/cm^3. What would be its volume?

8_murik_8 [283]

Given ,

Mass of sample of cobalt = 27 g

density of sample of cobalt = 9g/cm^3

We know that ,

Density = mass of sample/volume of sample

From that relation ,

We can deduce the following as

Volume = mass of sample/density of sample

Hence , required volume of sample of cobalt = 27 g /9 g/cm^3 = 3 cm^3

The volume is $\fbox{3cm cube}$

3 0

3 years ago