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. What is the mass, in grams, of a sample of 7.83 × 1024 atoms of helium (He)?

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# Tag: grams

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Janitor supply produces an industrial cleaning powder that requires 40 grams of material at $0.10 per gram and .25 direct labor hours at $12.00 per hour. overhead is assigned at the rate of $18 per direct labor hour. what is the total standard cost for one unit of product that would appear on a standard cost card? $7.00. $8.50. $11.50. $7.50. $25.00.

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How many grams of solute are present in 625 mL of 0.520 M KBr?

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16Al + 3S8 = 8Al2S3

We need to determine which reactants are the limiting and the excess. To determine this, we use the initial amounts of the reactants given above. We need to convert them into units of moles and use the balanced reaction to relate the substances calculating the amount needed to react all of the reactants. We do as follows:

63.8 g Al ( 1 mol Al / 26.98 g Al ) ( 3 mol S8 / 16 mol Al ) (256.48 g S / 1 mol S )= 113.72 g S8 needed to completely react

72.3 g S8 ( 1 mol S8 / 256.48 g S8) ( 16 mol Al / 3 mol S8 ) ( 26.98 g / mol ) = 40.56 g Al needed to completely react

Therefore, the excess would be Al and the limiting would be sulfur. The amount excess would be 63.8 g Al – 40.56 g Al = 23.24 g Al

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How many grams are there in 2.3 x 10^24 atoms of silver?

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What is the density of a block of aluminum that has mass 27 grams of and a volume 10 cm3? 2.7 g/cm3 270 g/cm3 0.37 g/cm3 0.37 cm3/g

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Margo boils 500mL of water to make 80 g of pasta. If Margo boils 2500mL of water, how many grams of pasta can she make?

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If 0.9 grams of calcium burnt in air the weight of product formed is?

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Each oxygen atom has a molar mass of 16 g/mol. The molar mass of oxygen gas is calculated below,

molar mass = 2 x (16 g/mol) = 32 g/mol

To determine the number of moles in 52.5 grams of oxygen, divide the given mass by the calculated molar mass.

n = 52.5 grams / (32 gram/ mol)

n = 1.64 moles

Thus, there are 1.64 moles of oxygen gas.

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b = 0.22 m^0.87

db/dt = 0.24 g/day at b = 23 g

where

b is the brain mass of the fetus

m is the total mass of the fetus

db/dt is the rate of change of the brain mass of the fetus

We are asked to get the rate of change of the total mass of the fetus

First, we take the first derivative of the given equation with respect to time

db/dt = 0.22 (0.87) m^(0.87-1) dm/dt

Next, simplify and substitute the given values. So,

0.24 g/day = 0.22(0.87)(23)^(0.87 -1 ) dm/dt

Solving for dm/dt

dm/dt = 1.88 g/day

The rate of change of mass of the fetus is 1.88 g/day.

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We let x be the mass of the white which is 45% gold and 55% platinum.

Mass of gold in white gold = m x 0.45

where m is the total mass.

From the given above, we formulate the equation that would allow us to determine the mass of white gold.

154 = x (0.45)

x = 342.22 g

Then, we determine the amount of platinum.

mass of platinum = (342.22 g)(0.55)

mass of platinum = 188.22 grams

Thus, 188.22 grams of platinum is needed.

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2H2 + O2 = 2H2O

We are given the amount of oxygen to react with hydrogen. To determine the amount of hydrogen needed for the oxygen to completely react, we use the balanced reaction to relate the substances. We do as follows:

64 g O2 ( 1 mol / 32 g ) ( 2 mol H2 / 1 mol O2 ) ( 2.02 g / 1 mol ) = 8.08 g of hydrogen gas needed

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Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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**Answer:**

The age of a rock is determined by the function:

…..[1]

where,

A(t) be the age of rock after t years

be the initial value of Isotope Q.

t be the number of years.

**As per the statement:**

A sample originally has 80 grams of Isotope Q, decays, and now has 20 grams of the isotope.

⇒ gram and A(t) = 20 grams

Substitute in [1] we have;

**Divide both sides by 80 we have;**

**Taking ln with base e both sides we have;**

⇒

**Divide both sides by 0.000002 we have;**

693147.18056 = t

or

t = 693147.18056 years

**Therefore, the current age of the sample, in years to the nearest thousand years is, 6,93,147 year**

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**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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N₂ + 3H₂ –> 2NH₃

The equation shows that every 3 moles of hydrogen, H2, there would be 2 moles of ammonia, NH3, that is going to be formed. Using this concept, we solve for the unknown in this item.

Since we are restricted only of the number of hydrogen, it becomes our limiting reactant.

(6 moles H2) x (2 moles NH3/3 moles H2) = *4 moles NH3*

Therefore, given enough amount of N2, the amount of NH3 that can be formed out of the 6 moles of H2 is equal to 4 moles.

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N₂ + 3H₂ –> 2NH₃

The equation shows that every 3 moles of hydrogen, H2, there would be 2 moles of ammonia, NH3, that is going to be formed. Using this concept, we solve for the unknown in this item.

Since we are restricted only of the number of hydrogen, it becomes our limiting reactant.

(6 moles H2) x (2 moles NH3/3 moles H2) = *4 moles NH3*

Therefore, given enough amount of N2, the amount of NH3 that can be formed out of the 6 moles of H2 is equal to 4 moles.

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**Answer:**

The point that lie on the line is:

** B. (1,1)**

**Step-by-step explanation:**

We are given that a line passes through the point (0,-1) and has a slope of 2.

We know that the equation of a line passing through (a,b) and having slope m is given by:

Here we have: (a,b)=(0,-1) and m=2

This means that the equation of line is:

Now we will check which option is true.

**A)**

** (2,1)**

when x=2

we have:

Hence, option: A is** incorrect.**

**B)**

** (1,1)**

when x=1

we have:

** Hence, option: B is correct.**

**C)**

** (0,1)**

when x=0

we have:

Hence, option: C is** incorrect.**

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**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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**p = Xsolv * Po sol**

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

**Answer: 30.6 torr**

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**Answer:**

The coefficient of CO₂ is 5.

**Explanation:**

Balancing the reaction:

___C₅H₁₂ + ___O₂ → ___CO₂ + ___H₂O

There are 5 C in the left side, so we put 5 on the right side:

___C₅H₁₂ + ___O₂ → 5CO₂ + ___H₂O

There are 12 H in the left side, so we put 6 as the coefficient of H₂O:

___C₅H₁₂ + ___O₂ → 5CO₂ + 6H₂O

Finally, there are 16 O in the right side, so we put 8 as the coefficient of O₂

___C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

*The coefficient of CO₂ is 5.*

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