There are two types of physical changes and chemical reactions- endothermic and exothermic. On the diagram below, which picture (A or B) is endothermic and which picture (A or B) is exothermic? Be sure to explain your reasoning for both.

Each ion has a single charge, one positive and one negative, so we need only one ion of each to balance the overall charge. When writing the ionic formula, we follow two additional conventions: (1) write the formula for the cation first and the formula for the anion next, but (2) do not write the charges on the ions.

Answer:

4.00 g/mL

Explanation:

Density is mass divided by volume (g/mL).

Mass of rock = 21.58

Volume of rock = 25.4 - 20.0 = 5.4mL

Density of rock = 21.58g / 5.4mL = 3.99629 g/mL

Round to the lowest number of significant figures which is three = 4.00 g/mL

The relative atomic mass of element A : 6.075 u

The elements in nature have several types of isotopes

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

Atomic mass is the average atomic mass of all its isotopes

Mass atom X = mass isotope 1 . % + mass isotope 2.% ...

Element A

mass number of isotope 1 = 6 , percent : 92.5%

mass number of isotope 2 = 7, percent : 7.5

Relative atomic mass of element A

[tex]\tt = 92.5\%\times 6+7.5\%\times 7\\\\=5.55+0.525=6.075~u[/tex]

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{2.39 \times {10}^{23} }{6.02 \times {10}^{23} } \\ = 0.39700996...[/tex]

We have the final answer as

Hope this helps you

Answer:

the market is largely driven by the growing population, increasing burden of chronic disease, and rising inclination toward targeted therapy.

Explanation:

also, the huge demand of biopharmaceutical is facilitated by an accelerating focus in research and related investment.

Answer:

Use formula of PV = nRT

Change formula to solve for Volume = nRT/P

R is a constant 0.08206

Convert C to Kelvin which is just +273

And turn mmHg into atm which is around 1 atm

Plug in and solve

Answer:

Distillation

Explanation:

A solution of water and ethanol are miscible. Hence, they can only be separated by a process known as distillation. Distillation is the process in which two or more constituents in a mixture are separated based on there difference in boiling points. The mixture is subjected to high heat and the one with the least boiling point distills/evaporates out first followed by the next least boiling point.

From the explanation above, it can be deduced that ethanol (with boiling point of 78°) will be distilled out while water remains in the boiling tube or container.

Answer:

seal them in a glass container in an atmosphere of argon (Ar) gas

Explanation:

Answer:

Electrical energy = 130000000 J and Heat energy = 520000000 J

Explanation:

Multiply the amount of joules from the last question (650000000) by .20 and .80. (Which are the percentages)

Answer:

26.1g

Explanation:

Cclf3

=35.5

F=54/101.5

Mass=mol*mm

=0.25*1015

=26.1g

Answer: The water vapor transfers thermal energy to the air.

Explanation:

It is incorrect because it should have a total of eight electrons with two electrons between each H and O

Lewis structure shows the form of bonds that occur in the valence electrons of an element or compound

This bonding usually occurs in covalent bonds

Valence electrons are electrons used in a chemical bond

The main group elements usually have valence electron configurations in the ns and np subshells, While the transition elements in the subshells (n-1) d and ns.

Element O has 6 valence electrons

Element H has 1 valence electron

To achieve stability, the element O needs 2 more electrons which are obtained from 2 electrons from the H element, while the H element needs 1 electron to be stable

So that a covalent bond is formed

Answer: Christy won Molly by 12cm

Explanation:

Ist step

Molly's ;ong jump was 118.3cm

Christy long jump was 51.18inches

2nd Step

we change christy score to cm so we can compare

1 inch = 2.54cm.

therefore 51.18 inches = 51.18 x 2.54= 129.9972cm

Christy won molly by 129.9971cm-118.3cm=11.69 rounded to 12cm

Christy won Molly by 12cm

Answer:

The presence of fructose in their diet

Explanation:

The independent variable in an experiment is the type of variable which is changed at intervals in order to study if it has a direct effect on the dependent variable.

The dependent variable in the experiment is the amount of weight gained by the mice in each group and the control group is the mice who drank the water without the fructose added.

Answer: what are options

Explanation:

Explanation: oatmeal cookies, and the independednt variable is the kind of cookie

Answer:

A

Explanation:

got it on edge

An echolocation refers to a method that relies on sound waves and is used by different animal species for navigation, communication, and finding food. Therefore, option A is correct.

Echolocation is a method used by bats, dolphins, and other animals to locate objects using reflected sound. This enables the animals to move around in complete darkness, allowing them to navigate, hunt, recognize friends and enemies, and avoid obstacles.

(1) To hunt for prey, bats make high-frequency sounds. (2) Sound waves are used by dolphins and other toothed whales to locate prey and navigate their surroundings. (3) Nocturnal oil birds use echolocation to navigate their surroundings, particularly in low-light conditions.

Echolocation is used to help with orientation, obstacle avoidance, food acquisition, and social interactions.

Thus, option A is correct.

To learn more about an echolocation, follow the link;

https://brainly.com/question/7828418

#SPJ6

Answer: 255 pm

Explanation: Hope this helps!

Answer:

They are in the same family, with similar characteristics.

Explanation:

The elements in a given group of the periodic table are in the same family and with similar characteristics.

Answer:

Explanation:

Convert mass in gms .. 987 gms

Density = mass/ volume

= 987/4.52 x102

= 2.18 g/mL

Answer:

The periodic table is organized in non-metals metals and metalloids, in in terms of trends and patterns you may want to talk about the the density of the elements or the mass of per unit of measurement of whatever you're going to use sorry that could be much help but I hope it helps.

Answer

Explanation:

an atom is usually define as a perfect balance of electrons and protons

Answer:

/D/ either absorbs or releases energy

Explanation:

During a phase change energy is either absorbed or released.

A phase change is a reversible process which occurs when a substance changes is its state from one form to another.

Phase changes are used to delineate physical changes.

Q must be supplied = 119523.3~J

The law of conservation of energy can be applied to heat changes, i.e. the heat received/absorbed is the same as the heat released  

Q in = Q out  

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

So from the question :

Q to the system(Q supplied) = Q water + Q steel vessel(Q gained)

[tex]\tt Q~supplied=m.c\Delta T(water)+m.c\Delta T(vessel)\\\\Q~supplied=375\times 4.18\times (100-35)+532\times 0.51(100-35)\\\\Q~supplied=101887.5+17635.8=119523.3~J[/tex]