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White raven [17]

3 years ago

11

Describe the 3 categories that the periodic table can be divided into. Be prepared to provide this information for an element on

the periodic table.

1 answer:

deff fn [24]3 years ago

4 0

Answer:

Metal, non-metal , and metaliod

Explanation:

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How does stem apply to science?<br><br> (i swear if yall just answer for points ima lose it)

vova2212 [387]

STEM is an acronym meaning

Science

Technology

Engineering

Mathematics

One of the main focuses of STEM courses is on science, so you will be learning about various types of science

This is an approach at learning to have students learn all four types of subjects in one class, based on real world applications.

8 0

3 years ago

Write a molecular equation for the precipitation reaction that occurs (if any) when the following solutions are mixed. If no rea

iragen [17]

Answer :

(A) The balanced molecular equation will be:

$K_2CO_3(aq)+Pb(NO_3)_2(aq)\rightarrow 2KNO_3(aq)+PbCO_3(s)$

(B) The balanced molecular equation will be:

$Li_2SO_4(aq)+Pb(CH_3COOH)_2(aq)\rightarrow 2LiCH_3COOH(aq)+PbSO_4(s)$

(C) The balanced molecular equation will be:

$Cu(NO_3)_2(aq)+Na_2S(aq)\rightarrow 2NaNO_3(aq)+CuS(s)$

(D) The balanced molecular equation will be:

$Sr(NO_3)_2(aq)+2KI(aq)\rightarrow \text{No reaction}$

Explanation :

Molecular equation : It is defined as a balanced chemical equation where the ionic compounds are expressed in the form of molecules rather than component of ions.

Precipitation reaction : It is defined as the reaction in which an insoluble salt formed when two aqueous solutions are combined.

The insoluble salt that settle down in the solution is known an precipitate.

Part A : potassium carbonate and lead(II) nitrate

The balanced molecular equation will be:

$K_2CO_3(aq)+Pb(NO_3)_2(aq)\rightarrow 2KNO_3(aq)+PbCO_3(s)$

In this reaction, lead carbonate is an insoluble salt and potassium nitrate is a soluble solution.

Part B : lithium sulfate and lead(II) acetate

The balanced molecular equation will be:

$Li_2SO_4(aq)+Pb(CH_3COOH)_2(aq)\rightarrow 2LiCH_3COOH(aq)+PbSO_4(s)$

In this reaction, lead sulfate is an insoluble salt and lithium acetate is a soluble solution.

Part C : copper(II) nitrate and sodium sulfide

The balanced molecular equation will be:

$Cu(NO_3)_2(aq)+Na_2S(aq)\rightarrow 2NaNO_3(aq)+CuS(s)$

In this reaction, Cuprous sulfide is an insoluble salt and sodium nitrate is a soluble solution.

Part D : strontium nitrate and potassium iodide

The balanced molecular equation will be:

$Sr(NO_3)_2(aq)+2KI(aq)\rightarrow 2KNO_3(aq)+SrI_2(aq)$

In this reaction, strontium iodide and potassium nitrate are soluble solution.

$Sr(NO_3)_2(aq)+2KI(aq)\rightarrow \text{No reaction}$

6 0

3 years ago

Why burning of fuel is a chemical change give 5 reasons to support your answer

frozen [14]

Answer:

Explanation:

1. New substances such as carbondioxide and water is formed.

2. There is evolution of gas bubbles. Gases are released.

3. There is either the absorption of energy or release of energy in form of light and energy.

4. The reaction is irreversible i.e it cannot be reversed, it is permanent once the reaction take place.

5. There is a change in both odor and smell.

A chemical change is a change where new substances are formed due to changes in the properties.

6 0

3 years ago

Sperm can be carried by _____ grains. ANSWERSSSSSSSSSSSSSSSSS O spore O stamen O pollen

7nadin3 [17]

What is pollen in the reproduction cycle of flowering plants?

A pollen grain is a microspore containing the male gametophyte, usually reduced to two undivided cells, each with one haploid (n) nucleus. These cells are surrounded by a very resistant wall, the exine, which generally has apertures, zones with less resistance which will allow the germination of the pollen tube.

Explanation of the reproduction cycle (cf diagram above)

A given species produces flowers bearing stamens. According to species, these flowers can be unisexual (stamens only) or bisexual (stamens and carpels).

The stamen anthers include 4 pollen sacs containing sporogenous cells (diploid=2n). These sporogenous cells undergo meiosis, each producing 4 microspores (haploid=n). Two nuclei are then formed by mitosis : the vegetative nucleus and the generative nucleus. The latter divides to form 2 sperms. Simultaneously the wall of the microspores becomes thicker and takes the characteristic shape of the species : it is a pollen grain (see: What are the morphological characteristics of pollen and spore grains?). In the majority of species, the 4 grains (resulting from the 4 microspores) split up into single grains; in some cases, they remain together (tetrad = group of 4 grains). When mature, pollen grains are released by the opening of the anthers.

A pollen grain is aimed at reaching another flower of the same species, bearing carpels. The ovaries contain ovules, in which meiosis occurs, then mitoses. It results in an embryo sac with 8 nuclei, among which an egg cell and 2 central cells. When a pollen grain arrives on another flower (see : How are the spores and pollen grains transported?), it is received by the stigmas.

The pollen grain germinates through an opening of the wall: the vegetative nucleus develops into a pollen tube which is guided by the style to the ovary, then enters the micropyle of an ovule. The pollen tube releases 2 sperm nuclei into the ovule: one of the sperms fuses with the egg cell into a zygote (2n), while the other sperm fuses with central nuclei and gives rise to albumen (= food source). There are generally several ovules in an ovary : each one can be fertilized by a distinct pollen grain.

Each fertilized ovule and its albumen form a seed that will develop into a new individual of this species. hope it works

4 0

3 years ago

Read 2 more answers

A factor that does no change in an experiment is the.

kvasek [131]

Answer:

A. Controlled variable

Explanation:

a controlled variable or a constant variable is a variable that doesnt change during an experiment

5 0

3 years ago