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Paha777 [63]
3 years ago
9

Questions

Chemistry
1 answer:
Ulleksa [173]3 years ago
6 0

Answers:

See below  

Step-by-step explanation:

1. Most food energy

(a) Pringles

Heat from Pringles + heat absorbed by water = 0

m₁ΔH  + m₂CΔT = 0

1.984ΔH + 100 × 4.184 × 18 = 0

1.984ΔH + 7530 = 0

ΔH = -7530/1.984 = -3800 J/g

(b) Cheetos

0.884ΔH + 418.4 × 13 = 0

ΔH = -5400/0.884 = -6200 J/g

Cheetos give you more food energy per gram.

(c) Snickers

Food energy = 215 Cal/28 g × 4184 J/1 Cal = 32 000 J/g

The food energy from Cheetos is much less than that from a Snickers bar

2. Experimental uncertainty

The experimental values are almost certainly too low.

Your burning food is heating up the air around it, so much of the heat of combustion is lost to the atmosphere.

3. Percent efficiency

Experimental food energy = 3800 J/g

Actual food energy = 150 Cal/28 g × 4184 J/1 Cal = 22 000 J/g

% Efficiency = Experimental value/Actual value × 100 %

                    = 3800/22 000 × 100 %

                    = 17 %

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What is the molar mass of Pb(SO4)2? Explain how you calculated this value.
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Isotopes called what are used to diagnose disease and to study environmental conditions
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7 0
3 years ago
#15 fill in the following table regarding ions
Natasha_Volkova [10]

Answer:

P^{3-}         Anion      Gained 3         18          

Sr^{2+}       Cation      Lost    2          36

Fe^{3+}       Cation     Lost    3          23

Explanation:

Looking at the ionic notation, the negative symbol (-) indicates that there are more electrons than protons and the positive symbol (+) indicates that there are more protons than electrons.

The number tells you how many was gained or lost.

To determine how many electrons are left, you base this off how many protons there are. The number of protons in an atom is expressed by the atomic number. In a stable atom, you have an equal number of protons and electrons.

Ions occur when electrons are gained or lost.

A cation is positively charged because it LOST an electron. Since there are more protons than electrons, the charge would be positive.

An anion is negatively charged because it gained an electron. Since there are more electrons than protons, the charge would be negative.

Using the explanation above, you can see how the answers were obtained. As for the last column, just use basic math to do this.

The atomic number of Phosphorus (P) is 15, so this means that there are 15 protons. Since it gained 3 electrons, just add 3 to 15:

15 + 3 = 18

Sr has an atomic number 38. Since it lost 2 electrons, just subtract 2 from the atomic number.

38-2 = 36

Fe has an atomic number 26. It lost 3 electrons, so we subtract again.

26-3 = 23

7 0
3 years ago
What is the mass of 2.47 moles of fluorine (<br> f. atoms? 0.130 g 7.69 g 46.9 g my answer 282 g
mixer [17]

The mass of 2.47 moles of fluorine atom is 46.9 g

calculation

mass of Fluorine= moles x molar mass

moles = 2.47 moles

molar mass of fluorine = 18.998 g/mol

mass is therefore= 2.47 moles x 18.008 g/mol = 46.9 g

3 0
4 years ago
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