Answer:
We need 1.1 grams of Mg
Explanation:
Step 1: Data given
Volume of water = 78 mL
Initial temperature = 29 °C
Final temperature = 78 °C
The standard heats of formation
−285.8 kJ/mol H2O(l)
−924.54 kJ/mol Mg(OH)2(s)
Step 2: The equation
The heat is produced by the following reaction:
Mg(s)+2H2O(l)→Mg(OH)2(s)+H2(g)
Step 3: Calculate the mass of Mg needed
Using the standard heats of formation:
−285.8 kJ/mol H2O(l)
−924.54 kJ/mol Mg(OH)2(s)
Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g)
−924.54 kJ − (2 * −285.8 kJ) = −352.94 kJ/mol Mg
(4.184 J/g·°C) * (78 g) * (78 - 29)°C = 15991.248 J required
(15991.248 J) / (352940 J/mol Mg) * (24.3 g Mg/mol) = 1.1 g Mg
We need 1.1 grams of Mg
Answer:
sound loudness is measured in decibels, A. True
There are essentially 5 states of matter-
1) Solid
2) Liquid
3) Gas
4) Plasma
5) Bose-Einstein Condensate
Plasma comprises of positive and negatively charged particles that are formed in extremely high temperature conditions. A characteristic of plasma is that it is not dense enough. The ions tend to be far apart, which makes them to spread out and imparts compressibility.
Ans B)
Gneiss is a sedimentary rock and granite is a metamorphic rock.
<h3>What are rocks?</h3>
Rocks are geological hard materials that are made up of various types which include:
- Sedimentary rocks: These are rocks that made up of various layers formed from sediments. Example is the gnesis.
- Metamorphic rocks: These are rocks that are form from pre existing rocks that undergoes some transformation. Example is granite
Therefore, Gneiss is a sedimentary rock and granite is a metamorphic rock.
Learn more about rocks here:
brainly.com/question/398139
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PH + pOH = 14
pH = 14 - pOH
pH = 14 - 8.7
pH = 5,3
This solution is <u>acidic</u>.
If pH<7 - acidic
If pH=7 - neutral
If pH>7 - basic
