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algol [13]
2 years ago
8

The nutritional recommended daily allowance (rda) of calcium is 1,300 mg for a 9-18-year-old. How many grams is this? How many a

toms of calcium is this?​
Chemistry
1 answer:
Simora [160]2 years ago
6 0

Answer:

1.3 grams and I think the atoms of calcium is 7, 829. 9

Explanation:

hope this helps!

You might be interested in
4.50 g of a certain Compound X, known to be made of carbon, hydrogen and perhaps oxygen, and to have a molecular molar mass of 1
Anna11 [10]

Answer:

\mathbf{C_{10}H_8}   ( Naphthalene )

Explanation:

Given that:

4.50 g of a Compound X is made up of Carbon , Hydron and Oxygen

It's molecular molar mass = 128 g/mol

Compound X undergoes combustion reaction and the product yield :

CO_2 with mass 15.47g and :

H_2O with mass 2.53 g

The objective is to use this information to determine the molecular formula of X.

We all know that ; number of moles = mass/molar mass

where the molar mass of H_2O is 18 g/mol

number of moles of H_2O product = 2.53 g/18 g/mol

number of moles of H_2O product = 0.1406 moles

Also; the molar mass of CO_2 product = 44 g/mol

number of moles of CO_2 product = 15.47g/ 44 g/mol

number of moles of CO_2 product =  0.3516 moles

number of moles of Compound X in the reactant side= 4.50 g /128 g/mol

number of moles of Compound X n the reactant side= 0.03516 moles

Now; number number of moles of CO_2 in reactant = 0.3516 moles/0.03516 moles

Now; number number of moles of CO_2 in reactant = 10

number of moles of H_2O reactant = 0.1406 moles × 2/0.03516

number of moles of H_2O reactant = 7.997 ≅ 8

Since we said the Compound X is known to be made of Carbon C , Hydrogen H and Oxygen O

Then the molecular formula can be written as :

\mathbf{C_{10}H_8O_{x}}

In order to find the x; we have

128  = (12 × 10 + 1 × 8 + 16 × x)

128 = 120 + 8 + 16x)

128  =  128 + 16 x

128 - 128 = 16 x

0 = 16 x

x = 0/16

x = 0

As x = 0 ; hence there are no oxygen present in the reaction

Thus; the molecular formula of Compound X = \mathbf{C_{10}H_8} which is also known as Naphthalene

5 0
3 years ago
It’s a test and only need 2 more problems!!!! Thank you and Appreciate it!!!
Mkey [24]

Answer:

the molar mass of propane (c3H8) is

12*3+1*8

=36+8=44

3 0
3 years ago
How are the three phrases of agriculture (shifting, labor-intensive, mechanized monoculture) different in terms of description,
natka813 [3]

Answer:

Explanation:

Shifting, labor intensive and monoculture are different in terms of description,restrictions and problem.

Shifting is an agriculture method in which an area if land is cultivated for a while and abandoned for the soil to regain and preserve it's fertility. It is done to restore soul fertility.

It has restrictions because it is done in places where there is large areas of land, if there is not large area of land, it will be done.

It can lead to defforestation because trees are cut fine for land cultivation and after a while the land is abandoned and trees are cut down some where else too.

Labor intensive refers to agricultural industry requiring or needing large amount of labor to produce agricultural products. Labor intensive is restricted to areas where there is low or no people who can engage in agricultural services.

Labor intensive require high skilled people which might not be available.

Monoculture is a farming system where by a single crop is cultivated in an area of land.

The problem of monoculture is that it displaces species and nutrients occuring naturally in an ecosystem.

Monoculture is restricted in areas where diversity of crops are needed.

4 0
3 years ago
The concentration of gallium in silicon is 5.0 × 10−7 at%. What is the concentration in kilograms of gallium per cubic meter?
Step2247 [10]

Answer:

[ Ga ] = 1.163 E-8 Kg/m³

Explanation:

  • %wt = [(mass Ga)/(mass Si)]*100 = 5.0 E-7 %

⇒ 5.0 E-9 = m Ga/m Si

assuming: m Si = 100 g = 0.1 Kg

⇒ m Ga = (5.0 E-9)*(0.1 Kg) = 5 E-10 Kg

∴ density (δ) Si = 2.33 Kg/m³

⇒ Volume Si = (0.1 Kg)*(m³/2.33 Kg) = 0.043 m³

⇒ [ Ga ] = (5 E-10 Kg)/(0.043 m³) = 1.163 E-8 Kg/m³

⇒ [ Ga ] =

3 0
3 years ago
What is the definition of specific heat? O A. The heat required to break the molecular bonds within a substance B. The total amo
snow_tiger [21]

Answer:

C

Explanation:

C .       specific heat =    J / gm-C

               

7 0
2 years ago
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