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ANTONII [103]
3 years ago
13

Which type of investigation is based on observation?

Chemistry
1 answer:
grigory [225]3 years ago
7 0

Answer:

Quantitative Observations

Explanation:

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A compound of a transition metal and iodine is 56.7% metal by mass.How many grams of the metal can be obtained from 630 g of thi
erma4kov [3.2K]

Answer:

357 g of the transition metal are present in 630 grams of the compound of the transition metal and iodine

Explanation:

In any sample of the compound, the percentage by mass of the transition metal is 56.7%. This means that for a 100 g sample of the compound, 56.7 g is the metal while the remaining mass, 43.3 g is iodine.

Given mass of sample compound = 630 g

Calculating the mass of iodine present involves multiplying the percentage by mass composition of the metal by the mass of the given sample;

56.7 % = 56.7/100 = 0.567

Mass of transition metal = 0.567 * 630 = 357.21 g

Therefore, the mass of the transition metal  present in 630 g of the compound is approximately 357 g

4 0
3 years ago
A chemist measures the enthalpy change ?H during the following reaction: Fe (s) + 2HCl (g) ? FeCl2 (s) + H2 (g) =?H?157.kJ Use t
erik [133]

Correct Question:

A chemist measures the enthalpy change ΔH during the following reaction: Fe(s) + 2HCl(g)-->FeCl2(s) + H2 ΔH=-157.0 kJ. Use this information to complete the table below. Round each of your answers to the nearest kJ/mol

Answer:

-314 kJ

+628 kJ

+157 kJ

Explanation:

The enthalpy change of a reaction measures the amount of heat that is lost or gained by it. If ΔH >0 the heat is gained, and the reaction is called endothermic, if ΔH<0, the heat is lost, and the reaction is called exothermic.

If the reaction is inverted, the value of ΔH is inverted too (the opposite endothermic reaction is exothermic), and if the reaction is multiplied by a constant, ΔH will be multiplied by it too.

1) 2Fe(s) + 4HCl --> 2FeCl2(s) + 2H2(g)

This reaction is the product of the given reaction by 2, so

ΔH = 2*(-157) = -314 kJ

2) 4FeCl2(s) + 4H2(g) --> 4Fe(s) + 8HCl(g)

This reaction is the inverted reaction given multiplied by 4, so

ΔH = 4*(157) = +628 kJ

3) FeCl2(s) + H2(g) --> Fe(s) + 2HCl

This reaction is the inverted reaction given, so

ΔH = +157 kJ

4 0
3 years ago
Oxygen freezes at -219°c and boils at -183°c in which state is oxygen at -200°c​
vova2212 [387]

oxygen is in gaseous state at this temperature

4 0
3 years ago
4 NH3 + 6 NO → 5 N2 + 6 H2O How many moles of NH3 are necessary to produce 0.824 mol N2?
GrogVix [38]
4 mol NH₃ → 5 mol N₂
x mol NH₃ → 0.824 mol N₂

x=0.824*4/5=0.6592 mol
6 0
3 years ago
Which type of bond is found between atoms of solid cobalt?
Vsevolod [243]
The answer is (3) metallic. Cobalt is a transition metal, so it can't be covalent bonds, which bond non-metals, therefore eliminating choice 1 and 2. Ionic bonds are between metals and non metals, but solid cobalt does not have a non metal, eliminating choice 4 as well. Metallic bonds are bonds between metals, therefore the answer is (3) metallic.
3 0
3 years ago
Read 2 more answers
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