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3 years ago

(Please answer asap/right now. :( )

Chemistry

1 answer:

Ganezh [65]3 years ago

8 0

Answer:

A. substance Y will float on top of substance X.

Explanation:

If an objet is more dense that other, the first one will sink because it weights more per militer, as you can see in the image below. In our case, Substance X is heavier than Y, that means that X will sink = Y will float.

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El NaCI corresponde a un elemento?

Schach [20]

Answer:

Sodio (Na), elemento químico del grupo de los metales alcalinos (Grupo 1 [Ia]) de la tabla periódica. El sodio es un metal blanco plateado muy suave. El sodio es el metal alcalino más común y el sexto elemento más abundante en la Tierra, y comprende el 2,8 por ciento de la corteza terrestre.

Explanation:

Espero que esto ayude a marcar el MÁS CEREBRAL !!!

7 0

3 years ago

Which regions on the periodic table can adopt positive and negative oxidation numbers?

Dennis_Churaev [7]

The region(s) of the periodic table which are made up of elements that can adopt both positive and negative oxidation numbers are the “non-metal” region. As we can see on the periodic table, the elements situated at the right side of the table have two oxidation states, one positive and the other a negative.

7 0

3 years ago

Complete combustion of a compound containing hydrogen and carbon produced 2.641 g of carbon dioxide and 1.442 grams of water as

klio [65]

The empirical formula of hydrocarbon is C₃H₈

The molecular formula of hydrocarbon is C₆H₁₆

Empirical formula calculation

Hydrocarbon contain carbon and hydrogen

Step 1: find the mass carbon (C) in carbon dioxide (CO₂) and hydrogen (H ) in water

mass of of element = molar mass of element/ molar mass molecule x total mass of molecule

From periodic table the molar mass of C =12, for CO₂ = 12+( 16 x2) =44 g/mol, for H = 1.00 g/mol, for H₂O = (2 x1)+16 = 18 g/mol

mass of C = 12/44 x 2.641 =0.7203 g

since there are 2 atom of H in H₂O the molar mass of H = 1 x2 = 2 g/mol

mass of H is therefore = 2/18 x 1.442 =0.1602 g

Step 2: find the moles of C and H

moles = mass÷ molar mass

moles of C = 0.7203 g÷ 12 g/mol = 0.060 moles

moles of H = 0.1602÷ 1 g/mol = 0.1602 moles

Step 3: find the mole ratio of C and H by dividing each mole by smallest mole ( 0.06)

for C = 0.06/0.06 =1

For H = 0.1602/0.06 =2.67

multiply by 3 to remove the decimal

For C = 1 x3 =3

For H = 2.67 x3 =8

therefore the empirical formula = C₃H₈

The molecular formula calculation

[C₃H₈]n = 88.1 g/mol

[12 x 3)+( 1 x8)]n =88.1 g/mol

44 n = 88.1

divide both side by 44

n=2

therefore [C₃H₈]₂ = C₆H₁₆

7 0

3 years ago

Read 2 more answers

To aid in the prevention of tooth decay, it is recommended that drinking water contains 0.900 ppm fluoride (F-). A) How many g o

Romashka-Z-Leto [24]

Answer:

a) 1.740 g of F- must be added to a cylindrical water reservoir

b) Grams of sodium fluoride, NaF, that contain this much fluoride:

3.84 g

Explanation:

Step 1. calculate the volume of the tank:

Volume of cylinder =

$\pi r^{2}h$ ,

Here r = radius of the cylinder = d/2

h = depth = 21.80m

$r=\frac{d}{2}$

$=\frac{3.36x10^{2}}{2}$

= 168 m

Volume =

$=\frac{22\times 168^{2}\times 21.80}{7}$

$=1.93\times 10^{6} m^{3}$

2.Convert ppm to g/m3 and Solve for mass of F-

$1ppm = 1g/m^{3}$

$0.9ppm = 0.9g/m^{3}$

Because both ppm and g/m3 are same quantity .

$g/m^{3} =\frac{mass\ of\ F-(g)}{Volume\ m^{3}}\times 10^{6}$

$0.9 =\frac{mass\ of\ F-}{1.93\times 10^{6} m^{3}}\times 10^{6}$

$mass\ of\ F- =1.740g$

mass of F- required = 1.740 g

3. Apply mole concept to calculate grams of sodium fluoride produced

mass of 1 mole of F2 = 38 g

mass of 1 mole of NaF = 42 g

(from periodic table calculate molar mass)

$2Na+F_{2}\rightarrow 2NaF$

Here 1 mole of F2 produce = 2 mole of NaF

So,

38 g of F2 produce = 2 x 42 g of NaF

38 g of F2 produce = 84 g of NaF

1 g of F2 produce = 84/38 g of NaF

1.74 g F2 produce =

$\frac {84}{38}\times 1.74$

1.74 g F2 produce = 3.84 g of NaF

3.84 g of NaF is produced

3 0

3 years ago

Why do scientists use stirbars in the laboratory?

andrew11 [14]

Answer:

A stir bar consists of a magnetic bar used to agitate a liquid mixture or solution

Explanation:

7 0

2 years ago