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3 years ago

15

Which of the following statements is true? Temperature is the same as heat. Heat can travel through a vacuum. Heat has shorter w

avelengths than visible light. All of the a

2 answers:

sergeinik [125]3 years ago

8 0

Your answer will be B Heat can travel through a vacuum.

miss Akunina [59]3 years ago

4 0

The answer would be number 1

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PLeaseee ITS Timedddd + BrainlIESTT

uysha [10]

Answer:

d. 12.3 grams of Al2O3

Explanation:

The balanced chemical equation of this chemical reaction is as follows:

4Al + 3O2 --> 2Al2O3

Based on the balanced equation, 4 moles of aluminum (limiting reagent) reacts to form 2 moles of aluminum oxide (Al2O3).

First, we need to convert the mass of aluminum to moles using the formula;

mole = mass/molar mass

Molar mass of Al = 27g/mol

mole = 6.50/27

= 0.241mol of Al.

Hence, if 4 moles of aluminum (limiting reagent) reacts to form 2 moles of aluminum oxide (Al2O3).

Then, 0.241mol of Al will produce (0.241 × 2/4) = 0.241/2 = 0.121mol of Al2O3.

Convert this mole value to molar mass using mole = mass/molar mass

Molar mass of Al2O3 = 27(2) + 16(3)

= 54 + 48

= 102g/mol

mass = molar mass × mole

mass = 102 × 0.121

mass of Al2O3 = 12.34grams.

5 0

3 years ago

How many moles would be in 85.OmL of 0.750M KOH?

Harlamova29_29 [7]

Answer: There are 0.0637 moles present in 85.0 mL of 0.750 M KOH.

Explanation:

Given: Volume = 85.0 mL (1 mL = 0.001 L) = 0.085 L

Molarity = 0.750 M

It is known that molarity is the number of moles of solute present in liter of a solution.

Therefore, moles present in given solution are calculated as follows.

$Molarity = \frac{moles}{Volume (in L)}\\0.750 M = \frac{moles}{0.085 L}\\moles = 0.0637 mol$

Thus, we can conclude that there are 0.0637 moles present in 85.0 mL of 0.750 M KOH.

7 0

3 years ago

Practice Problem: True Stress and Strain A cylindrical specimen of a metal alloy 49.7 mm long and 9.72 mm in diameter is stresse

amm1812

Answer:

The true stress required = 379 MPa

Explanation:

True Stress is the ratio of the internal resistive force to the instantaneous cross-sectional area of the specimen. True Strain is the natural log to the extended length after which load applied to the original length. The cold working stress – strain curve relation is as follows,

σ(t) = K (ε(t))ⁿ, σ(t) is the true stress, ε(t) is the true strain, K is the strength coefficient and n is the strain hardening exponent

True strain is given by

Epsilon t =㏑ (l/l₀)

Substitute㏑(l/l₀) for ε(t)

σ(t) = K(㏑(l/l₀))ⁿ

Given values l₀ = 49.7mm, l =51.7mm , n =0.2 , σ(t) =379Mpa

379 x 10⁶ = K (㏑(51.7/49.7))^0.2

K = 379 x 10⁶/(㏑(51.7/49.7))^0.2

K = 723.48 MPa

Knowing the constant value would be same as the same material is being used in the second test, we can find out the true stress using the above formula replacing the value of the constant.

σ(t) = K(㏑(l/l₀))ⁿ

l₀ = 49.7mm, l = 51.7mm, n = 0.2, K = 723.48Mpa

σ(t) = 723.48 x 106 x (㏑(51.7/49.7))^0.2

σ(t) = 379 MPa

The true stress necessary to plastically elongate the specimen is 379 MPa.

6 0

3 years ago

Read 2 more answers

Calcium hydride reacts with water to form calcium hydroxide (aqueous) and hydrogen gas. Write a balanced chemical equation for t

DanielleElmas [232]

Answer:

$CaH_2(s) +2H_2O(l) \rightarrow Ca(OH)_2 (aq) + 2H_2 (g)$

Explanation:

$CaH_2(s) +H_2O(l) \rightarrow Ca(OH)_2 (aq) + H_2 (g)$

In this reaction, calcium is balanced in either side. No. of atoms of 'H' and 'O' are not balanced. To balance O atoms, multiply $H_2O$ by 2. Now the reaction becomes:

$CaH_2(s) +2H_2O(l) \rightarrow Ca(OH)_2 (aq) + H_2 (g)$

Now, to balance H atoms, multiply H2 by 2.

$CaH_2(s) +2H_2O(l) \rightarrow Ca(OH)_2 (aq) + 2H_2 (g)$

Now, each element is balanced.

8 0

3 years ago

17 moles of oxygen is equal to

mixas84 [53]

Answer:

271.9897999999996

Explanation:

have a good day :)

3 0

3 years ago