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2 years ago

An ion of calcium has a charge of 2+. The ion contains 18 electrons. How many protons does a neutral atom of calcium possess?

Chemistry

1 answer:

Elza [17]2 years ago

7 0

Answer:

Explanation:

The ion and the neutral atom both contain 20 protons. Generally the protons stay in the nucleus forever.

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Red #40 has an acute oral LD50 of roughly 5000 mg dye/1 kg body weight. This means if you had a mass of 1 kg, ingesting 5000 mg

FrozenT [24]

Answer:

350 g dye

0.705 mol

2.9 × 10⁴ L

Explanation:

The lethal dose 50 (LD50) for the dye is 5000 mg dye/ 1 kg body weight. The amount of dye that would be needed to reach the LD50 of a 70 kg person is:

70 kg body weight × (5000 mg dye/ 1 kg body weight) = 3.5 × 10⁵ mg dye = 350 g dye

The molar mass of the dye is 496.42 g/mol. The moles represented by 350 g are:

350 g × (1 mol / 496.42 g) = 0.705 mol

The concentration of Red #40 dye in a sports drink is around 12 mg/L. The volume of drink required to achieve this mass of the dye is:

3.5 × 10⁵ mg × (1 L / 12 mg) = 2.9 × 10⁴ L

8 0

3 years ago

What are valency and radicals

PolarNik [594]

Valency- it means the combing capacity if an element.
 radical- it is an atom, molecule, or ion that has unpaired valence electrons or an open electron shell.

6 0

3 years ago

Calculate the equilibrium constant k for the isomerization of glucose-1-phosphate to fructose-6-phosphate at 298 k. express your

k0ka [10]

We cannot solve this problem without using empirical data. These reactions have already been experimented by scientists. The standard Gibb's free energy, ΔG°, (occurring in standard temperature of 298 Kelvin) are already reported in various literature. These are the known ΔG° for the appropriate reactions.

glucose-1-phosphate⟶glucose-6-phosphate ΔG∘=−7.28 kJ/mol
fructose-6-phosphate⟶glucose-6-phosphate ΔG∘=−1.67 kJ/mol

Therefore, the reaction is a two-step process wherein glucose-6-phosphate is the intermediate product.

glucose-1-phosphate⟶glucose-6-phosphate⟶fructose-6-phosphate

In this case, you simply add the ΔG°. However, since we need the reverse of the second reaction to end up with the terminal product, fructose-6-phosphate, you'll have to take the opposite sign of ΔG°.

ΔG°,total = −7.28 kJ/mol + 1.67 kJ/mol = -5.61 kJ/mol

Then, the equation to relate ΔG° to the equilibrium constant K is

ΔG° = -RTlnK, where R is the gas constant equal to 0.008317 kJ/mol-K.
-5.61 kJ./mol = -(0.008317 kJ/mol-K)(298 K)(lnK)
lnK = 2.2635
K = e^2.2635
K = 9.62

6 0

3 years ago

Read 2 more answers

Select the correct answer.

vitfil [10]

Answer:

The answer is B

Explanation:

6 0

3 years ago

Read 2 more answers

An average person expends about 845 kilojoules of energy per hour of walking. Suppose a person eats 2 baked potatoes with butter

ExtremeBDS [4]

Answer:

$\large\boxed{2hours}$

Explanation:

You will need to use the conversion between food calories, calories and joules.

$1\text { nutritional calorie }= 1,000cal\\ \\ 1cal=4.184joule$

From a nutritional table (from the internet) you can obtain the amount of nutritional calories for each type macronutrient: carbohydrates, protein, and fat.

Macronutrient food calories

Carbohydrate 4 cal/g

Protein 4 cal/g

Fat 9 cal/g

To convert food calories to regular calories, mutiply by the conversion factor:

$1=1,000cal/\text{nutritional calorie}$

Macronutrient calories

Carbohydrate 4,000 cal/g

Protein 4,000 cal/g

Fat 9,000 cal/g

To convert regular calories to joules, multiply by the conversion factor:

$1=4.184 joule/1cal$

Macronutrient energy in joules

Carbohydrate 16,736 joule/g

Protein 16,736 joule/g

Fat 37,656 joule/g

Now you can multiply the grams of each macronutrient in one potato by its energy content:

Macronutrient energy/gram × grams = total energy

Carbohydrate 16,736 joule/g × 37 g = 619,232 joules

Protein 16,736 joule/g × 4.3 g = 71,968.8 joules

Fat 37,656 joule/g × 4 g = 150,624 joules

Total = 619,232 joules + 71,968.8 joules + 150,624 joules = 841,820.8 joules.

Since they are two potatoes, multiply by 2: × 841,820.8 joules = 1,683,641.6 joules.

Divide by 1,000 to convert to kilojoules = 1,683.64 kilojoules

Divide the total energy from the two potatoes by the energy that an average person expend per hour of walking (845 kilojoules of energy per hour):

$1,683.64kilojoules/845kilojouesl/hour=1.99hours\approx 2hours$

7 0

3 years ago