The temperature reading of –14°C corresponds to a Kelvin reading of:

Which of the following choices results in a decrease in the overall density of a product? Question 5 options: Increase the volum

Elza [17]

Answer:

When the volume of product increases.

When the weight of the product decreases.

Option (a) and (d) are correct.

Explanation:

The overall density of the product can be decreased:

a. Increase the volume of the product (and keep the material same)

d. Decrease the weight of the product ( and keep the same material ).

Density is calculated as the ratio of mass to the volume.

Density is inversely related to volume and directly related to mass.

So, when the mass of the product is increased then the density will increase keeping the material same. Density will also increase when the volume of the product decreased.

8 0

3 years ago

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A sample of TNT, C7H5N3O6 , has 8.94 × 1021 nitrogen atoms. How many hydrogen atoms are there in this sample of TNT?

Bess [88]

Answer:

1.49×10²² atoms of H are contained in the sample

Explanation:

TNT → C₇H₅N₃O₆

1 mol of this has 7 moles of C, 5 moles of H, 3 moles of N and 6 moles of O

Let's determine the mass of TNT.

Molar mass is = 227 g/mol

As 1 mol has (6.02×10²³) NA atoms, how many moles are 8.94×10²¹ atoms.

8.94×10²¹ atoms / NA = 0.0148 moles

So this would be the rule of three to determine the mass of TNT

3 moles of N are in 227 g of compound

0.0148 moles of N are contained in (0.0148 .227) / 3 = 1.12 g

Now we can work with the hydrogen.

227 grams of TNT contain 5 moles of H

1.12 grams of TNT would contain (1.12 .5) / 227 = 0.0247 moles

Finally let's convert this moles to atoms:

0.0247 mol . 6.02×10²³ atoms / 1 mol = 1.49×10²² atoms

8 0

3 years ago

The beakers in the picture above are labeled according to the ionic solutions they contain. What metal or metals could replace c

tangare [24]

Explanation:

When a metal replaces another metal in solution, we say such a reaction has undergone a single displacement reaction.

In such a reaction, metal higher up in the activity series replaces another one due to their position.

To known the metal or metals that will replace the given copper, we need to reference the activity series of metals.

Every metal higher than copper in the series will displace copper from the solution.

So, there metals are: potassium, sodium, lithium, barium, strontium etc.

8 0

3 years ago

If you collect 1.75 L of hydrogen gas during a lab experiment when the room temperature is 23oC and the barometric pressure is 1

ziro4ka [17]

Answer:

$n=0.0747mol$

Explanation:

Hello,

In this case, since we can consider hydrogen gas as an ideal gas, we check the volume-pressure-temperature-mole relationship by using the ideal gas equation:

$PV=nRT$

Whereas we are asked to compute the moles given the temperature in Kelvins, thr pressure in atm and volume in L as shown below:

$n=\frac{105kPa*\frac{0.009869atm}{1kPa}*1.75L}{0.082\frac{atm*L}{mol*K}*(23+273.15)K} \\\\n=0.0747mol$

Best regards.

8 0

3 years ago

Cytotoxic t cells can attack target cells with which chemical weapons?

Aneli [31]

Answer:

secrete cytotoxic substance which triggers apoptosis of target cell.

Explanation:

Cytotoxic T cells have cell surface receptor which recognizes the antigen present on the receptor of target cell. This interaction initiates the process of killing of target cell.

After interaction cytotoxic t cell release cytotoxic substance called granzyme and perforin. Granzyme triggers apoptosis through the activation of caspases or by making the release of cytochrome c and activation of the apoptosome.

Perforin make pores in the cell and its action is similar to complement membrane attack complex. Therefore cytotoxic substances are released by Tc cells which trigger apoptosis of target cell.

4 0

3 years ago