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2 years ago

How does the curing basically take place?

Chemistry

1 answer:

Sphinxa [80]2 years ago

4 0

Explanation:

The first involves keeping the surface of the concrete moist by the use ponding, spraying/sprinkling, damp sand or damp hessian.

The second prevents the loss of moisture from the concrete by covering it with polythene sheeting or leaving the formwork in place.

The third involves the use of spray or roller applied curing compounds.

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Which compound is an electrolyte? 1. H2O 2. C2H6 3. H3PO4 4. CH3OH

uysha [10]

An electrolyte is a substance that releases ions when it is dissolved in water. Electrolytes are divided into salts, ions and bases. In this case, the electrolyte is H₃PO₄ as it releases H+ ions and PO₄⁻³ ions when it is dissolved in water.

6 0

3 years ago

Oxygen has 6 valence electrons. How many electrons does an atom of oxygen need to become stable?

SOVA2 [1]

Answer:

Two electrons

Explanation:

According to the octet rule, atoms must bond to each other, sharing electrons among themselves in an attempt to complete their valence shell (last layer of the electrosphere). In other words, an atom becomes stable when it has 8 electrons in its valence shell.

Oxygen atoms have six electrons in their valence shell, so to achieve the stability suggested by the octet rule (eight electrons), these atoms share two electrons, forming one oxygen gas (O₂) molecule.

8 0

4 years ago

Read 2 more answers

A student made the Lewis dot diagram of a compound as shown. Mg is written with two dots shown on its top. Cl is written on the

blsea [12.9K]

Answer:

The dots were not properly located and arrows are not used in Lewis structures

Explanation:

If we intend to write a Lewis structure for a compound, that lewis structure must consist of only dots. These dots actually show the valence electrons on the outermost shell of the molecule.

We do not involve arrows when writing dot electron structures for compounds. The valence electrons of magnesium ought not to be written together because they are not a lone pair, rather they are two unpaired electrons. The use of an arrow suggests a coordinate covalent bond which is not the case here.

The correct lewis structure for MgCl2 is shown in the image attached to this answer.

7 0

3 years ago

A student measures the mass of an 8 cm block of brown sugar to be 12.9 g. What is the density of

horrorfan [7]

Answer:

0.0025g/cm³

Explanation:

Given parameters:

Mass of the brown sugar = 12.9g

dimension of the sugar = 8cm

unknown:

density of the sugar = ?

Solution

Density is defined as the mass per unit volume of a substance. The expression is given below:

Density = $\frac{mass}{volume}$

We know the mass of the substance but the volume is unknown:

Volume of the brown sugar = l x bx h = 8x8x8 = 512cm³

Density of the brown sugar = $\frac{12.9}{512}$ = 0.0025g/cm³

8 0

3 years ago

A cylinder of oxygen gas has a volume of 10.0 liters at 7.66 atm and 27.0oC. The cylinder is heated until the pressure is 428 kP

iris [78.8K]

Answer:

Explanation:

428 x 10³ Pa = 4.28 x 10⁵ Pa = 4.28 atm

We shall use the gas equation

P₁V₁ / T₁ = P₂V₂ / T₂

7.66 x 10 / ( 273 + 27 ) = 4.28 x 30 / T₂

.255 = 128.4 / T₂

T₂ = 503.53

= 503.53 - 273 = 230.53⁰C .

6 0

3 years ago