All categories

2 years ago

A higher temperature of fresh concrete results in a __________ hydration of cement.

Chemistry

1 answer:

Readme [11.4K]2 years ago

4 0

Answer:

more rapid

Explanation:

A higher temperature of fresh concrete results in a more rapid hydration of cement. This causes reduction in the setting time of the cement, also known as accelerated setting of the cement.

It also reduces the workability of the concrete; as it makes the movement of aggregates harder by reducing the lubricating effect of the cement.

You might be interested in

A gem has a mass of 4.50 g. When the gem is placed in a graduated cylinder 12.00 mL of water, the water level rises to 13.45 mL.

Mandarinka [93]

Displaced volume :

Final volume - Initial volume

13.45 mL - 12.00 mL => 1.45 mL

Mass = 4.50 g

Therefore:

density = mass / volume

D = 4.50 / 1.45

D = 3.103 g/mL

6 0

2 years ago

One ATP molecule's hydrolysis releases 7.3 kcal/mol of energy (∆G = −7.3 kcal/mol of energy). If it takes 2.1 kcal/mol of energy

Oxana [17]

Answer:

One ATP molecule's hydrolysis can move 3 ions of Sodium (Na+) across the menbrane.

Explanation:

As you can see, the energy provided by ATP is enough for moving 3 ions of Na+. Each ion needs +2.1 kcal/mol of energy.

If we multiply by 3 the energy for moving across the membrane= +6.3 kcal/mol

By adding the energy from ATP:

ΔGTotal=6.3-7.3= -1 kcal/mol

7 0

2 years ago

Given six molecules, identify the molecules with polar bonds and the molecules that are polar.CCl4, CH3Cl, H20, CO2, O2

Nikitich [7]

Answer:

Non-polar compounds: $CCl_4$ , $O_2$ , $CO_2$

Polar compounds: $CH_3Cl$ , $H_2O$

Explanation:

For this question, we must start with the Lewis structure for each molecule and then we can do their respective analysis:

-) $CCl_4$

In this case, we have 4 equal atoms attached to the central atom. Therefore, we have the same magnitude of electronegativity. Chlorine atoms have different and opposite directions. Therefore due to the orientation the dipole moments cancel and the net dipole moment will be zero and the molecule will be non-polar.

-) $O_2$

In this case, we have a linear structure in which the magnitude of the dipole moment is the same, but the direction is the opposite. Therefore the dipole moments are canceled and the molecule will be non-polar.

-) $CO_2$

In this case, we also have a linear structure in which the magnitude of the dipole moment is the same, but the direction is the opposite. Therefore the dipole moments are canceled and the molecule will be non-polar.

-) $CH_3Cl$

For this molecule, we have a different atom. The hydrogen atom, therefore the magnitude of one of the atoms attached to the central atom is different and the magnitude of the net dipole moment will be different from zero and the molecule will be polar.

-) $H_2O$

For this molecule, due to the structure of the molecule, the dipole moments of oxygens will not have a totally opposite configuration. Therefore, the net dipole moment will be different from zero and the molecule will be polar.

See figure 1 to further explanations

I hope it helps!

5 0

2 years ago

A high school class is discussing whether a particular discovery in chemistry has had a positive impact on society. Which questi

AURORKA [14]

The most important question for the students to answer is what the discovery did to society. Did it change society in any way or better something?

3 0

2 years ago

At 10°c one volume of water dissolves 3.10 volumes of chlorine gas at 1.00 atm pressure. what is the henry's law constant of cl2

s344n2d4d5 [400]

Answer is: 0,133 mol/ l· atm.
T(chlorine) = 10°C = 283K.
p(chlorine) = 1 atm.
V(chlorine) = 3,10 l.
R - gas constant, R = 0.0821 atm·l/mol·K.
Ideal gas law: p·V = n·R·T
n(chlorine) = p·V ÷ R·T.
n(chlorine) = 1atm · 3,10l ÷ 0,0821 atm·l/mol·K · 283K = 0,133mol.
Henry's law: c = p·k.
k - Henry's law constant.
c - solubility of a gas at a fixed temperature in a particular solvent.
c = 0,133 mol/l.
k = 0,133 mol/l ÷ 1 atm = 0,133 mol/ l· atm.

4 0

2 years ago