I'm kinda in a rush but take your time!Thx! 1.What was Henri Becquerel studying when he accidentally discovered radioactivity?

What can the reader conclude about the effects of hurricanes?

Ludmilka [50]

They cause most of their damage when they reach land

7 0

2 years ago

Which unit can be used to express the concentration of a solution?

exis [7]

Answer: (3) ppm

Explanation: Concentration is defined as the amount of solute dissolved in a known amount of the solvent or a solution.

Parts per million (ppm) is used to express the concentration when a very small quantity of solute is present in a large quantity of the solution. It is defined as the mass of solute present in one milion $(10^6)$ parts by mass of the solution.

$ppm=\frac{\text {mass of Solute}}{\text {Mass of solution}}\times 10^6$

L/s is used to express flow rate.

J/g is used to express energy per unit mass.

kPa is used to express pressure.

6 0

3 years ago

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When polonium-210 emits an alpha particle, the child isotope has an atomic mass of

Sergeeva-Olga [200]

Answer: The child isotope has an atomic mass of 206.

Explanation:

Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.

General representation of an element is given as: $_Z^A\textrm{X}$

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

General representation of alpha decay :

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha$

$_{84}^{210}\textrm{Po}\rightarrow_{82}^{206}\textrm{Pb}+_2^4\textrm{He}$

8 0

3 years ago

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A solution is made using 148.5 g of dimethyl ether (MM = 46.07 g/mol) and 90.0 g of methanol (MM = 32.04 g/mol). What is the mol

Mariulka [41]

Answer:

0.534

Explanation:

Mole fraction can be calculated using the formula:

Mole fraction = number of moles of solute ÷ number of moles of solvent and solute (solution).

In this question, solute is dimethyl ether while the solvent is methanol.

Mole (n) = mass (M) ÷ molar mass (MM)

Mole of solute (dimethyl ether) = 148.5 ÷ 46.07

= 3.22moles.

Mole of solvent (methanol) = 90 ÷ 32.04

= 2.81moles.

Total moles of solute and solvent = 3.22 + 2.81 = 6.03moles.

Mole fraction of dimethyl ether = number of moles of dimethyl ether ÷ number of moles of solution (dimethyl ether + methanol)

Mole fraction = 3.22/6.03

= 0.534

6 0

3 years ago

Consider the following statements about weeding and identify the incorrect one.

dolphi86 [110]

Answer:

b) Weeding is the process of growing weed

Explanation:

Wedding is an agricultural process carried out to ensure maximum you won't do. It is the process by which weeds i.e. unwanted plants are removed.

As rightly stated in the question;

- Weeding is either done by manual means e.g Cutlasses or use of weedicides, which are chemicals.

- Weeding is best done during tiling operations.

The incorrect option is that "Weeding is the process of growing weed" rather it is a process of removing weed.

4 0

2 years ago