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vova2212 [387]
3 years ago
5

What are periods on the periodic table? How many are there?

Chemistry
1 answer:
Brums [2.3K]3 years ago
8 0
A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons. Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements.
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Aqueous hydrochloric acid reacts with solid manganese(iv) oxide to form aqueous manganese(ii) chloride, liquid water and chlorin
maria [59]
4HCl + MnO₂ → MnCl₂ + 2H₂O + Cl₂

2Cl⁻ → Cl₂ + 2e⁻                                     
MnO₂ + 4H⁺ + 2e⁻ → Mn²⁺ + 2H₂O         

2Cl⁻ + MnO₂ + 4H⁺ → Cl₂ + Mn²⁺ + 2H₂O
7 0
4 years ago
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How much heat is released as the temperature of 465 g of water drops from 75.0°C to 18.2°C?
Aleks [24]

The heat released : -110560.632 J

<h3>Further explanation</h3>

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

<h3>Known</h3>

m =465 g

c water = 4.186 J/gram °C

∆T = temperature difference = 18.2 - 75 = - 56.8 °C

Then the heat :

\tt Q=m.c.\Delta T\\\\Q=465\times 4.186\times -56.8\\\\Q=\boxed{\bold{-110560.632~J}}\rightarrow -=exothermic

3 0
3 years ago
Pleaseeeee answer quick
alexdok [17]

Answer:

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6 0
3 years ago
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Use logarithmic properties to solve the following equation log3 5x+ log3 7= 4 leave your answer in fraction form please
Salsk061 [2.6K]

Explanation:

Adding logs of same base is equivalent to multiplying the arguments. You get:

log_{3}(35x)  = 4

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Elza [17]

Answer:

rivers

Explanation:

7 0
3 years ago
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