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Rama09 [41]
3 years ago
10

Extra points!

Chemistry
2 answers:
Dima020 [189]3 years ago
8 0
Grinding a glass: Physical Change
Rusting of Iron: Chemical Change
Burning a candle: Chemical Change
Sanding a wood: Physical Change
noname [10]3 years ago
3 0

Answer:

1A

2B

3B

4A

Explanation:

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A sample of hydrated magnesium sulfate (MgSO4)
yaroslaw [1]

Answer:

MgSO4.7H2O

Explanation:

Let the formula for the hydrated magnesium sulphate be MgSO4.xH2O

Mass of the hydrated salt (MgSO4.xH2O) = 12.845g

Mass of anhydrous salt (MgSO4) = 6.273g

Mass of water molecule(xH2O) = Mass of the hydrated salt — Mass of anhydrous salt = 12.845 — 6.273 = 6.572g

Now,we can obtain the number of mole of water molecule present in the hydrated salt as follows:

Molar Mass of hydrated salt (MgSO4.xH2O) = 24 + 32 + (16x4) + x(2 + 16) = 24 + 32 + 64 + x(18) = 120 + 18x

Mass of xH2O/ Molar Mass of MgSO4.xH2O = Mass of water / mass of hydrated salt

18x/120 + 18x = 6.572/12.845

Cross multiply to express in linear form

18x x 12.845 = 6.572(120 + 18x)

231.21x = 788.64 + 118.296x

Collect like terms

231.21x — 118.296x = 788.64

112.914x = 788.64

Divide both side by 112.914

x = 788.64 /112.914

x = 7

Therefore the formula for the hydrated salt (MgSO4.xH2O) is MgSO4.7H2O

6 0
2 years ago
I need to know 5 and 6
irina [24]
6-cumbustion reaction
7 0
2 years ago
Which best represents the reaction of calcium and zinc carbonate (ZnCO3) to form calcium carbonate (CaCO3) and zinc? Ca → ZnCO3
artcher [175]
Ca + ZnCO3 → CaCO3 + Zn
3 0
3 years ago
Read 2 more answers
What are some factors that might cause our percent yield to be greater than 100%? What are some factors that might cause it to b
belka [17]
<span>In the field of science, usually, the product of an experiment is computed ahead to understand if it reached a specific objective. It would reach greater than 100% of percent yield if the factors include faster reaction rates; proper handling of the reactants, no outside contaminants, and the procedure of the experiment is followed smoothly. It would reach lesser than 100% percent yield if the experiment is not followed, external factors such as contamination from the environment (wind, moisture, etc). </span>
8 0
3 years ago
When radium-226 (atomic number-88) decays by emitting an alpha particle it becomes _____.
topjm [15]

Answer:

d. Radon-222

Explanation:

²²⁶₈₈Ra → ²²²₈₆Rn  + ⁴₂He

Alpha particle is a helium nucleus with mass number 4 and atomic number 2. According to the law of conversation of mass, the sum of the mass number and atomic number must be equal on both side of the reaction.  

Since the mass number of Ra is 226 and that of He is 4. The mass number of the unknown element must be 226 - 4 = 222.  

Since the atomic number of Ra is 88 and that of He is 2. The atomic number of the unknown element must be 88 - 2 = 86.  

Now looking in the periodic table Radon is the only element with atomic number 86.  

3 0
3 years ago
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